HDU 2037 - 今年暑假不AC（贪心 + 动态）

来源：互联网发布：北京四达时代通讯网络编辑：程序博客网时间：2024/06/05 20:37

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2037

贪心算法：

#include<iostream>#include<algorithm>using namespace std;struct TV{int begin;int end;}Tv[105];bool cmp(TV a,TV b){return a.end < b.end;} int main(){int n, i;while(cin >> n && n != 0){int count = 1;for(i = 0; i < n; i++){cin >> Tv[i].begin >> Tv[i].end;}sort(Tv,Tv+n,cmp);int End=Tv[0].end;for(i=1; i<n; i++){if(Tv[i].begin >= End){count++;    End = Tv[i].end;}}cout << count << endl;}return 0;}

动态规划：

#include <stdio.h>#include <stdlib.h>struct c{    int x;    int y;    int ord;}d[100];int cmp(const struct c *a, const struct c *b){    if ((*a).x == (*b).x)        return (*a).y - (*b).y;    else        return (*a).x - (*b).x;}int main(void){    int i, j, n, max;    while (scanf("%d", &n), n)    {        for (max = i = 0; i < n; i++)        {            scanf("%d%d", &d[i].x, &d[i].y);            d[i].ord = 1;        }        qsort(d, n, sizeof(struct c), cmp);        d[n-1].ord = 1;        for (i = n - 2; i >= 0; i--)        {            for (j = i + 1; j < n; j++)            {                if (d[i].y <= d[j].x && d[i].ord < d[j].ord + 1)                    d[i].ord = d[j].ord + 1;            }            if (max < d[i].ord)                max = d[i].ord;        }        printf("%d\n", max);    }    return 0;}