PAT甲1057 Stack (30)

#include <stdio.h>
#include <stdlib.h>
#include <cstdio>
#include <cstring>
#include <string>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <math.h>
#include <map> 
#include <vector>
using namespace std;

const int maxn=317;
int A[100010],N,length=0;
int harsh[100010]={0};
int block[317]={0};

char s[20];

int outh(int k)
{
    int sum=0;
    int i=0;
    while(sum+block[i]<k)
    {
        sum+=block[i];
        i++;
    }
    int index=i*316;
    while(sum+harsh[index]<k)
    {
        sum+=harsh[index];
        index++;
    }
    return index;
}

int main()
{
    scanf("%d",&N);
    for(int i=0;i<N;i++)
    {
        scanf("%s",&s);
        if(strcmp(s,"Push")==0)
        {
            int a;
            scanf("%d",&a);
            A[length++]=a;
            harsh[a]++;
            block[a/316]++;
        }
        else if(strcmp(s,"Pop")==0)
        {
            if(length==0)
            {
                printf("Invalid\n");
            }
            else
            {
                length--;
                printf("%d\n",A[length]);
                harsh[A[length]]--;
                block[A[length]/316]--;
            }
        }
        else if(strcmp(s,"PeekMedian")==0)
        {
            if(length==0)
            {
                printf("Invalid\n");
            }
            else
            {
                if(length%2==1)
                {
                    int a=outh((length+1)/2);
                    printf("%d\n",a);
                }
                else
                {
                    int a=outh(length/2);
                    printf("%d\n",a);
                }
            }
        }
    }
    system("pause");
    return 0;
}