HDU_3183_RMQ

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;

char a[1005],ans[1005];
int dp[1005][20];

int Min(int x,int y)
{
    return a[x] <= a[y] ? x : y;
}

void rmq_init(int len)
{
    for(int i = 0;i < len;i++)  dp[i][0] = i;
    for(int j = 1;(1<<j) < len;j++)
    {
        for(int i = 0;i+(1<<j)-1 < len;i++)
        {
            dp[i][j] = Min(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
        }
    }
}

int rmq_query(int l,int r)
{
    int k = (int)(log((double)(r-l+1))/log(2.0));
    return Min(dp[l][k],dp[r-(1<<k)+1][k]);
}

int main()
{
    int n,i;
    while(~scanf("%s%d",a,&n))
    {
        int len = strlen(a);
        rmq_init(len);
        n = len-n;
        int pos = 0,num = 0;
        while(n)
        {
            pos = rmq_query(pos,len-n);
            ans[num++] = a[pos++];
            n--;
        }
        for(i = 0;i < num && ans[i] == ‘0‘;i++);
        if(i == num)    printf("0\n");
        else
        {
            for(;i < num;i++)   printf("%c",ans[i]);
            printf("\n");
        }
    }
    return 0;
}