HDU 4296 Buildings

貪心

//轉載至http://blog.ac521.org/?p=614#include <cstdio>#include <cstring>#include <algorithm>#include <iostream>using namespace std; struct node{    int x, y;}num[100005]; bool cmp(node a, node b){    return a.x + a.y < b.x + b.y || a.x + a.y == b.x + b.y && a.x < b.x;} int main(){    int n, m, i, j, k;    while(~scanf("%d", &n)){        for(i = 0; i < n; i ++){            scanf("%d%d", &num[i].x, &num[i].y);        }        sort(num, num + n, cmp);        __int64 sum = 0, maxx = -10, m;                 for(i = 0; i < n; i ++){            m = sum - num[i].y;            if(m > maxx) maxx = m;            sum += num[i].x;        }        if(maxx < 0) printf("0\n");        else printf("%I64d\n", maxx);    }}