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Codeforces Round #665 (Div. 2)

2020-08-22 03:01:09 作者：互联网

Codeforces Round #665 (Div. 2)

A. Distance and Axis

如果$B$在$O$左边，那么只能是定值$OA$

如果$B$在$OA$中间，那么必然小于等于$OA$且奇偶性和$OA$相同

$B$在$A$右边的情况显然不如$B$和$A$重合

所以分$k\le n$和$k>n$分类讨论即可

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 2e5+7;

void solve(){
    int n, k;
    sci(n); sci(k);
    if(k<=n){
        if((k&1)==(n&1)) cout << 0 << endl;
        else cout << 1 << endl;
    }else cout << k - n << endl;
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    int tt; for(sci(tt); tt--; solve());
    return 0;
}

B. Ternary Sequence

显然要拿$A$的$2$和$B$的$1$组合，尽量得到大的值，然后拿$A$的$0$和$2$去和$B$的$2$组合，尽量避免出现负数，如果$A$还有$1$，$B$还有$2$，那么没办法只能组合了，剩下的数怎么组合贡献都是$0$

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 2e5+7;

void solve(){
    int x, y, z, a, b, c;
    sci(x); sci(y); sci(z); sci(a); sci(b); sci(c);
    int ret = min(z,b) * 2;
    z -= ret / 2; b -= ret / 2;
    int d = min(x,c);
    x -= d; c -= d;
    d = min(z,c);
    z -= d; c -= d;
    ret -= c * 2;
    cout << ret << endl;
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    int tt; for(sci(tt); tt--; solve());
    return 0;
}

C. Mere Array

考虑三个数$a,b,c$，$a$是数列中最小的数，$b ≡ 0 \mod a $且$c≡0\mod a$，那么通过$a$可以使得$a,b,c$任意排序

所以考虑把原序列排序，找出那些和原序列值不同的位置，如果这些位置上的值都能被最小值整除，那么就可以得到排序后的序列

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 2e5+7;

void solve(){
    int n; sci(n);
    vi A(n); for(int &x : A) sci(x);
    int x = *min_element(all(A));
    vi B(A);
    sort(all(B));
    for(int i = 0; i < n; i++){
        if(A[i]==B[i]) continue;
        if(A[i]%x!=0){
            cout << "NO" << endl;
            return;
        }
    }
    cout << "YES" << endl;
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    int tt; for(sci(tt); tt--; solve());
    return 0;
}

D. Maximum Distributed Tree

考虑计算每条边的贡献，可以发现每条边对$sz_v\cdot (n-sz_v)$个点对距离有贡献，其中$v$为边对应的子节点

考虑把边按贡献数排序，因子也排序，贡献大的赋的值也要尽量大，如果$m<=n-1$的话就给前$m$大贡献的边赋值对应的因子，否则给后$n-2$条边赋值对应小的因子，然后剩下的乘积赋给贡献最大的边

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 2e5+7;
const int MOD = 1e9+7;
vi G[MAXN];
int n, m, sz[MAXN];
vl cont;
void dfs(int u, int par){
    sz[u] = 1;
    for(int v : G[u]){
        if(v==par) continue;
        dfs(v,u);
        sz[u] += sz[v];
        cont << (1ll * sz[v] * (n - sz[v])); 
    }
}

void solve(){
    sci(n);
    for(int i = 1; i <= n; i++) G[i].clear();
    for(int i = 1; i < n; i++){
        int u, v;
        sci(u); sci(v);
        G[u] << v; G[v] << u;
    }
    sci(m);
    vi f(m);
    for(int &x : f) sci(x);
    sort(all(f),greater<int>());
    cont.clear();
    dfs(1,0);
    sort(all(cont),greater<LL>());
    LL ret = 0;
    if(m<=n-1){
        for(int i = 0; i < m; i++) ret = (ret + cont[i] % MOD * f[i]) % MOD;
        for(int i = m; i < n - 1; i++) ret = (ret + cont[i]) % MOD;
    }else{
        LL prod = 1;
        for(int i = 0; i < m - n + 2; i++) prod = prod * f[i] % MOD;
        for(int i = m - n + 2; i < m; i++) ret = (ret + cont[i-m+n-2+1] % MOD * f[i]) % MOD;
        ret = (ret + cont[0] % MOD * prod) % MOD;
    }
    cout << ret << endl;
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    int tt; for(sci(tt); tt--; solve());
    return 0;
}

E. Divide Square

考虑固定横向的边，初始正方形的块数是$1$，竖着的边和横着的边每有一个交点，都会多分出来一块

所以问题转化为计算交点数量，这个用扫描线就完事了

注意联通正方形两端的边会多分割出一块来

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 1e6+7;
const int lim = 1000000;
struct SegmentTree{
    int sum[MAXN<<2], l[MAXN<<2], r[MAXN<<2];
    #define ls(rt) rt << 1
    #define rs(rt) rt << 1 | 1
    void build(int L, int R, int rt = 1){
        l[rt] = L, r[rt] = R;
        if(L + 1 == R) return;
        int mid = (L + R) >> 1;
        build(L,mid,ls(rt)); build(mid,R,rs(rt));
    }
    void modify(int pos, int x, int rt = 1){
        sum[rt] += x;
        if(l[rt] + 1 == r[rt]) return;
        int mid = (l[rt] + r[rt]) >> 1;
        if(pos<mid) modify(pos,x,ls(rt));
        else modify(pos,x,rs(rt));
    }
    int qsum(int L, int R, int rt = 1){
        if(L>=r[rt] or l[rt]>=R) return 0;
        if(L<=l[rt] and r[rt]<=R) return sum[rt];
        return qsum(L,R,ls(rt)) + qsum(L,R,rs(rt));
    }
}ST;
int n, m;
pii line[MAXN];
vector<pii> vec[MAXN];
void solve(){
    sci(n); sci(m);
    for(int i = 1; i <= n; i++){
        int y; sci(y);
        sci(line[y].first), sci(line[y].second);
    }
    ST.build(0,lim+1);
    ST.modify(0,1); ST.modify(lim,1);
    LL ret = 1;
    for(int i = 1; i <= m; i++){
        int x; sci(x);
        int a, b; sci(a); sci(b);
        if(b-a==lim) ret++;
        if(!a){
            ST.modify(x,1);
            vec[b] << pii(x,-1);
        }else vec[a] << pii(x,1);
    }
    for(int i = 1; i <= lim; i++){
        for(auto &p : vec[i]) if(p.second==1) ST.modify(p.first,p.second);
        if(line[i].first + line[i].second) ret += ST.qsum(line[i].first,line[i].second+1) - 1;
        for(auto &p : vec[i]) if(p.second==-1) ST.modify(p.first,p.second);
    }
    cout << ret << endl;
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    solve();
    return 0;
}

F. Reverse and Swap

建一棵线段树，显然线段树是满二叉树

考虑$reverse(k)$操作，我们可以先打懒标记，然后不断下传，直到遇到线段树上某个节点$rt$且$r_{rt}-l_{rt}=2^k$的时候，我们可以把$reverse(k)$这个操作变为交换两个儿子，然后分别再对两个儿子进行$reverse(k-1)$

$swap(k)$这个操作也可以打懒标记，然后遇到节点$rt$满足$r_{rt}-l_{rt}=2^{k+1}$的时候，我们交换两个儿子即可

可以发现两个$reverse(k)$可以抵消，两个$swap(k)$也可以抵消，所以考虑用二进制来存懒标记，然后用异或来打标记

然后合在一起考虑的时候就分类讨论一下即可

如果只有$reverse(k)$，直接交换两个儿子，然后分别加上$reverse(k-1)$的标记
如果只有$swap(k-1)$标记，交换两个儿子就好了
都有的情况，那就不用交换儿子，直接给两个儿子分别加上$reverse(k-1)$标记即可

注意要把标记全部下传然后清空

view code

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define LL long long int
#define vi vector<int>
#define vl vector<LL>
#define all(V) V.begin(),V.end()
#define sci(x) scanf("%d",&x)
#define scl(x) scanf("%I64d",&x)
#define pii pair<int,int>
#define pll pair<LL,LL>
#define cmax(a,b) ((a) = (a) > (b) ? (a) : (b))
#define cmin(a,b) ((a) = (a) < (b) ? (a) : (b))
#define debug(x)  cerr << #x << " = " << x << endl
function<void(void)> ____ = [](){ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);};
template <typename T> void operator << (vector<T> &__container, T x){ __container.push_back(x); }
template <typename T> ostream& operator << (ostream &out, vector<T> &__container){ for(T _ : __container) out << _ << ' '; }
const int MAXN = 1e6+7;
int n, q, A[MAXN];

struct SegmentTree{
    int ls[MAXN<<2], rs[MAXN<<2], tot, root;
    LL sum[MAXN];
    int swp[MAXN<<2], rev[MAXN<<2];
    #define pushup(rt) sum[rt] = sum[ls[rt]] + sum[rs[rt]]
    void build(int L, int R, int &rt){
        rt = ++tot;
        if(L + 1 == R){
            sum[rt] = A[L];
            return;
        }
        int mid = (L + R) >> 1;
        build(L,mid,ls[rt]); build(mid,R,rs[rt]);
        pushup(rt);
    }
    void pushdown(int rt, int l, int r){
        int len = r - l;
        int bit = __builtin_ctz(len);
        if(rev[rt]>>bit&1){
            if(swp[rt]>>(bit-1)&1){
                rev[rt] ^= (1 << bit) ^ (1 << (bit - 1));
                swp[rt] ^= (1 << (bit - 1));
            }else{
                rev[rt] ^= (1 << bit) ^ (1 << (bit - 1));
                std::swap(ls[rt],rs[rt]);
            }
        }else if(swp[rt]>>(bit-1)&1){
            swp[rt] ^= (1 << (bit - 1));
            std::swap(ls[rt],rs[rt]);
        }
        rev[ls[rt]] ^= rev[rt]; rev[rs[rt]] ^= rev[rt];
        swp[ls[rt]] ^= swp[rt]; swp[rs[rt]] ^= swp[rt];
        rev[rt] = swp[rt] = 0;
    }
    void swap(int k){ swp[root] ^= (1 << k); }
    void reverse(int k){ rev[root] ^= (1 << k); }
    void modify(int pos, int x, int l, int r, int rt){
        if(l + 1 == r){
            sum[rt] = x;
            return;
        }
        pushdown(rt,l,r);
        int mid = (l + r) >> 1;
        if(pos < mid) modify(pos,x,l,mid,ls[rt]);
        else modify(pos,x,mid,r,rs[rt]);
        pushup(rt);
    }
    LL qsum(int L, int R, int l, int r, int rt){
        if(l>=R or L>=r) return 0;
        if(L<=l and r<=R) return sum[rt];
        pushdown(rt,l,r);
        int mid = (l + r) >> 1;
        return qsum(L,R,l,mid,ls[rt]) + qsum(L,R,mid,r,rs[rt]);
    }
}ST;
void solve(){
    sci(n); sci(q);
    for(int i = 0; i < (1 << n); i++) sci(A[i]);
    ST.build(0,1<<n,ST.root);
    while(q--){
        int type; sci(type);
        if(type==1){
            int x, k; sci(x), sci(k);
            ST.modify(x-1,k,0,1<<n,ST.root);
        }else if(type==2){
            int k; sci(k);
            ST.reverse(k);
        }else if(type==3){
            int k; sci(k);
            ST.swap(k);
        }else{
            int l, r; sci(l); sci(r);
            printf("%I64d\n",ST.qsum(l-1,r,0,1<<n,ST.root));
        }
    }
}
int main(){
    #ifndef ONLINE_JUDGE
    freopen("Local.in","r",stdin);
    freopen("ans.out","w",stdout);
    #endif
    solve();
    return 0;
}

标签：rt,__,container,int,665,Codeforces,vector,Div,define
来源： https://www.cnblogs.com/kikokiko/p/13544146.html