HDU 4883 TIANKENG’s restaurant(區間選點)

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HDU 4883 TIANKENG’s restaurant

題目連結

題意：給定一些時間作為區間，和一個人數，問要安排多少人去看管（一個人只能看管一個人)

思路：普通的區間選點問題，一個區間拆成一個進入點一個出去點，然後排序迴圈求答案即可

代碼：

#include <cstdio>#include <cstring>#include <algorithm>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;}