HDU 4883 TIANKENG’s restaurant

题目链接

题意：给定一些时间作为区间，和一个人数，问要安排多少人去看管（一个人只能看管一个人)

思路：普通的区间选点问题，一个区间拆成一个进入点一个出去点，然后排序循环求答案即可

代码：

#include 
  
   
#include 
   
     #include 
    
      using namespace std; const int N = 20005; struct Man { int v, t; Man() {} Man(int v, int t) {this->v = v; this->t = t;} } m[N]; bool cmp(Man a, Man b) { if (a.t != b.t) return a.t < b.t; return a.v < b.v; } int n, t, mn; int main() { scanf("%d", &t); while (t--) { mn = 0; scanf("%d", &n); for (int i = 0; i < n; i++) { int a, b, c, d, e; scanf("%d%d:%d%d:%d", &a, &b, &c, &d, &e); int t1 = b * 60 + c; int t2 = d * 60 + e; m[mn++] = Man(a, t1); m[mn++] = Man(-a, t2); } sort(m, m + mn, cmp); int ans = 0, sum = 0; for (int i = 0; i < mn; i++) { sum += m[i].v; ans = max(ans, sum); } printf("%d\n", ans); } return 0; }