[luoguP2434] [SDOI2005]区间（贪心）

传送门

简单贪心

——代码

#include <cstdio>
#include <iostream>
#include <algorithm>

int n, l, r;
struct node
{
    int x, y;
}p[50001];

inline bool cmp(node x, node y)
{
    return x.x < y.x;
}

inline int max(int x, int y)
{
    return x > y ? x : y;
}

int main()
{
    int i;
    scanf("%d", &n);
    for(i = 1; i <= n; i++) scanf("%d %d", &p[i].x, &p[i].y);
    std::sort(p + 1, p + n + 1, cmp);
    l = p[1].x;
    r = p[1].y;
    for(i = 2; i <= n; i++)
    {
        if(p[i].x > r)
        {
            printf("%d %d
", l, r);
            r = 0;
        }
        if(!r)
        {
            l = p[i].x;
            r = p[i].y;
        }
        else r = max(r, p[i].y);
    }
    printf("%d %d
", l, r);
    return 0;
}