#include <cstdio>#include <iostream>#include <algorithm>#include <queue>#include <stack>#include <climits>#include <cstring>#include <cmath>#include <map>#include <set>#define INF 100000000using namespace std;struct node{int x,y;};node a[1005];int n;int ma[1005][1005];int dp[1005];void print(int max,int q){if(max == 1){printf("%d\n",q+1);return ;}printf("%d\n",q+1);for(int i = 0;i < n;i++){if(ma[q][i] && dp[i] == max-1){print(max-1,i);break;}}}int fun(node &x,node &y){if(x.x < y.x && x.y > y.y) return 1;return 0;}int dfs(int cur){int& ret = dp[cur];if(ret > 0) return ret;ret = 1;for(int i = 0;i < n;i++){if(ma[cur][i]){ret = max(dfs(i)+1,ret);}}return ret;}int main(){while(scanf("%d%d",&a[n].x,&a[n].y)!=EOF) n++;memset(ma,0,sizeof(ma));for(int i = 0;i < n;i++){for(int j = 0;j < n;j++){if(fun(a[i],a[j]) > 0){ma[i][j] = 1;}}}for(int i = 0;i < n;i++){dfs(i);}int maxn;int max = -1;for(int i = 0;i < n;i++){if(dp[i] > max){maxn = i;max = dp[i];}} cout << max << endl;print(max,maxn);return 0;}
，旅行是一种病。一旦感染了，你就再也无法摆脱。
