Nescafe27 探险队（dp)

#include<set>
#include<map>
#include<cmath>
#include<queue>
#include<vector>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int N = 100100;
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,n) for(int i=1;i<=n;i++)
#define For(i,l,r) for(int i=l;i<=r;i++)

int n,x,y,dp[N],cnt;
pair<int,int> poi[N];

bool equal(pair<int,int> A,pair<int,int> B){return (A.first==B.first&&A.second==B.second);}
bool cmp(pair<int,int>A,pair<int,int> B){
    if(A.second==B.second) return A.first<B.first;
    else                   return A.second<B.second;
}
int main(){
    scanf("%d",&n);
    Rep(i,n){
        scanf("%d%d",&x,&y);
        if(x+y>=n) continue;
        poi[++cnt]=make_pair(y,n-x);
    }
    sort(poi+1,poi+cnt+1,cmp);
    dp[0]=0;int j=1;
    Rep(i,n){
        dp[i]=dp[i-1];
        if(poi[j].second==i){
            while(j<=cnt&&poi[j].second==i){
                int k=j;
                while(equal(poi[j],poi[k])&&k<=cnt) k++;
                dp[i]=max(dp[i],dp[poi[j].first]+min(k-j,poi[j].second-poi[j].first));
                j=k;
            }
        }
    }
    printf("%d\n",n-dp[n]);
    return 0;
}