p3389 高斯消元模板题(浮点）

#pragma GCC optimize(3)
#pragma GCC optimize(2)
#include <map>
#include <set>
// #include <array>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <iostream>
#include <stdlib.h>
#include <algorithm>
// #include <unordered_map>

using namespace std;

typedef long long ll;
typedef pair<int, int> PII;

#define Time (double)clock() / CLOCKS_PER_SEC

#define sd(a) scanf("%d", &a)
#define sdd(a, b) scanf("%d%d", &a, &b)
#define slld(a) scanf("%lld", &a)
#define slldd(a, b) scanf("%lld%lld", &a, &b)

const int N = 100 + 20;
const int M = 1e5 + 20;
const int mod = 1e9 + 7;
const double eps = 1e-6;

int n;
double a[N][N];

int gauss(){
    int c, r;
    for(c = 1, r = 1; c <= n; c ++){
        int t = r;
        for(int i = r + 1; i <= n; i ++){
            if(fabs(a[t][c]) < fabs(a[i][c])){
                t = i;
            }
        }
        if(fabs(a[t][c]) < eps) continue;

        for(int i = c; i <= n + 1; i ++) swap(a[t][i], a[r][i]);

        for(int i = n + 1; i >= c; i --){
            a[r][i] /= a[r][c];
        }

        for(int i = r + 1; i <= n; i ++){
            if(fabs(a[r][c]) > eps){
                for(int j = n + 1; j >= c; j --){
                    a[i][j] -= a[i][c] * a[r][j];
                }
            }
        }
        r ++;
    }

    if(r < n + 1) return -1;

    for(int i = n; i >= 1; i --){
        for(int j = i + 1; j <= n; j ++){
            a[i][n + 1] -= a[i][j] * a[j][n + 1];
        }
    }
    return 1;
}

void solve()
{
    sd(n);

    for(int i = 1; i <= n; i ++){
        for(int j = 1; j <= n + 1; j ++){
            scanf("%lf", &a[i][j]);
        }
    }

    int ans = gauss();

    if(ans == -1){
        puts("No Solution");
    }
    else{
        for(int i = 1; i <= n; i ++){
            printf("%.2lf\n", a[i][n + 1]);
        }
    }
    
}

int main()
{
#ifdef ONLINE_JUDGE
#else
    freopen("/home/jungu/code/in.txt", "r", stdin);
    // freopen("/home/jungu/code/out.txt", "w", stdout);
    // freopen("/home/jungu/code/out.txt","w",stdout);
#endif
    // ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T = 1;
    // sd(T);
    // init();
    // int cas = 1;
    while (T--)
    {
        // printf("Case #%d:", cas++);
        solve();
    }

    return 0;
}

标签：const,int,scanf,浮点,高斯消,--,include,p3389,define
来源： https://www.cnblogs.com/jungu/p/13462081.html