HDU 5240 Exam（贪心水题）

Problem Description

As this term is going to end, DRD needs to prepare for his final exams.

DRD has n exams. They are all hard, but their difficulties are different. DRD will spend at least ri hours on the i-th course before its exam starts, or he will fail it. The i-th course's exam will take place ei hours later from now, and it will last for li hours. When DRD takes an exam, he must devote himself to this exam and cannot (p)review any courses. Note that DRD can review for discontinuous time. 

So he wonder whether he can pass all of his courses. 

No two exams will collide. 

 

Input

First line: an positive integer T≤20 indicating the number of test cases.
There are T cases following. In each case, the first line contains an positive integer n≤105, and n lines follow. In each of these lines, there are 3 integers ri,ei,li, where 0≤ri,ei,li≤109. 

 

Output

For each test case: output ''Case #x: ans'' (without quotes), where x is the number of test cases, and ans is ''YES'' (without quotes) if DRD can pass all the courses, and otherwise ''NO'' (without quotes). 

 

Sample Input

2
3
3 2 2
5 100 2
7 1000 2
3
3 10 2
5 100 2
7 1000 2

 

Sample Output

Case #1: NO
Case #2: YES

 

Source

The 2015 ACM-ICPC China Shanghai Metropolitan Programming Contest

 

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水题。

ps的代码：

#include <bits/stdc++.h>
using namespace std;

const int MAXN = 1e5 + 5;

struct Node {
    int r;
    int e;
    int l;
} w[MAXN];

bool cmp(Node a, Node b)
{
    return a.e < b.e;
}

int main()
{
    int t;
    int n;
    int i;
    int spa;
    int cas = 0;

    scanf("%d", &t);

    while (t--) {
        scanf("%d", &n);
        for (i = 0; i < n; ++i) {
            scanf("%d%d%d", &w[i].r, &w[i].e, &w[i].l);
        }
        sort(w, w + n, cmp);
        printf("Case #%d: ", ++cas);
        spa = w[0].e;
        spa -= w[0].r;
        if (spa < 0) {
            printf("NO
");
            continue;
        }

        for (i = 1; i < n; ++i) {
            spa += w[i].e - (w[i - 1].e + w[i - 1].l);
            spa -= w[i].r;
            if (spa < 0) {
                printf("NO
");
                continue;
            }
        }
        printf("YES
");
    }

    return 0;
}