1422 环形dp

就是将序列拓展之后dp，来达到环形的效果

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#define MAX 100007using namespace std;int n;int a,b;int v[MAX<<1];int main ( ){    while ( ~scanf ( "%d" , &n ) )    {       int sum = 0;       int temp = 0;       int ans = 0;       for ( int i = 1 ; i <= n ; i++ )       {            scanf ( "%d%d" ,&a , &b );            v[i] = v[i+n] = a - b;           // cout << v[i] << " ";       }        for ( int i = 1 ; i <= 2*n ; i++ )       {           sum += v[i];           if ( sum >= 0 ) temp++;           ans = max ( ans , temp );           if ( sum < 0 )                temp = sum = 0;       }       printf ( "%d\n" , min ( ans , n ) );    }}