Leetcode 1011. 在 D 天内送达包裹的能力(DAY 179)---- 二分查找学习期
作者:互联网
文章目录
原题题目
代码实现(首刷超时 TLE 50/85 dp)
class Solution {
public:
int shipWithinDays(vector<int>& weights, int days) {
vector<vector<int>> dp(weights.size(),vector<int>(weights.size(),0));
for(int i=0;i<weights.size();++i)
{
for(int j=i;j<weights.size();++j)
{
if(i == j) dp[i][j] = weights[j];
else dp[i][j] = dp[i][j-1] + weights[j];
}
}
vector<int> now_min(weights.size(),0),pre_min(now_min),tmp_zero(pre_min);
vector<bool> now_visit(weights.size(),false),pre_visit(now_visit),tmp_false(now_visit);
int ret = INT_MAX;
for(int i=0;i<days;++i)
{
now_visit = tmp_false;
now_min = tmp_zero;
for(int start=i;start<weights.size();++start)
{
if(start && !pre_visit[start-1]) continue;
for(int end=start;end<weights.size();++end)
{
now_visit[end] = true;
if(!start)
{
now_min[end] = dp[start][end];
continue;
}
if(!now_min[end]) now_min[end] = max(pre_min[start-1],dp[start][end]);
else now_min[end] = min(now_min[end],max(pre_min[start-1],dp[start][end]));
}
}
pre_visit = now_visit;
pre_min = now_min;
if(pre_visit.back()) ret = min(ret,pre_min.back());
}
return ret;
}
};
代码实现(首刷看了点思路点拨后 二分自解)
class Solution {
public:
int shipWithinDays(vector<int>& weights, int days) {
int left = 0,right = 0,sum = 0;
for(const auto& num:weights)
{
left = max(left,num);
right += num;
}
sum = right;
while(left < right)
{
int mid = (left + right)/2;
int tmpsum = 0;
int day = 1,pos = 0;
while(day <= days && pos < weights.size())
{
if(tmpsum + weights[pos] > mid)
{
tmpsum = 0;
++day;
}
else
tmpsum += weights[pos++];
}
if(day > days) left = mid+1;
else right = mid;
}
return left;
}
};
标签:end,min,int,1011,----,start,weights,now,Leetcode 来源: https://blog.csdn.net/qq_37500516/article/details/120570664