链接:https://www.icpc.camp/contests/4mYguiUR8k0GKE
Partial Sum
Input
The input contains zero or more test cases and is terminated by end-of-file. For each test case: The first line contains three integers n, m, C. The second line contains n integers a1, a2, . . . , an.
? 2 ≤ n ≤ 105
? 1 ≤ 2m ≤ n + 1
? |ai |, C ≤ 104
? The sum of n does not exceed 106 .
题意:
给出n个数,每次选连续的一段数,已经被选作起点或终点的点不能再被选作起点与终点。
题解:
由于是绝对值 ,|sum|=max(cal[a]-cal[b],cal[b]-cal[a]);
而贪心的做法是将所有前缀和+0,共n+1个元素进行排序。
每次取出最大值和最小值相减即为最优解
#include <bits/stdc++.h> using namespace std; const int maxn=1e5+10; int cal[maxn]; int main() { int n,m,C; while(cin>>n>>m>>C) { cal[0]=0; for(int i=1;i<=n;i++) { int num; scanf("%d",&num); cal[i]=cal[i-1]+num; } sort(cal,cal+1+n); long long ans=0; for(int i=1;i<=m;i++) { int kk=abs(cal[i-1]-cal[n-i+1]); if(kk<=C)break; ans+=(kk-C); } cout<<ans<<endl; } return 0; }
原文地址:https://www.cnblogs.com/carcar/p/9025274.html
时间: 2024-10-09 13:17:11