codeforce 2A-2B

2A直接写,最多用个字符串hash,

#include<iostream>
#include<string>
#include<fstream>
using namespace std;

struct PI
{
    int point;
    int lastRound;
    int maxpoint;
};

PI record[99991];

unsigned int ELFHash(char* str)
{
    unsigned int hash=0;
    unsigned int x=0;
    while(*str)
    {
        hash=(hash<<4)+(*str++);
        if((x=hash&0xf0000000)!=0)
        {
            hash^=(x>>24);
            hash&=~x;
        }
    }
    return (hash&0x7fffffff);
}

int main()
{
    ifstream fin("2A.txt");
    memset(record,0,sizeof(record));
    string str[1002];
    int pt[1002];
    int n;
    cin>>n;
    
    for(int i=1;i<=n;i++)
    {
        int po;
        cin>>str[i]>>po;
        pt[i]=po;
        int hashIndex=ELFHash(const_cast<char*>(str[i].c_str()))%99991;
        record[hashIndex].point+=po;
        if(record[hashIndex].point>record[hashIndex].maxpoint)
        {
            record[hashIndex].maxpoint=record[hashIndex].point;
            
        }record[hashIndex].lastRound=i;


    }

    int maxpoint=0,leastround=1200;

    for(int i=0;i<99991;i++)
    {
        if(record[i].point>maxpoint)
        maxpoint=record[i].point;
    }

    for(int i=0;i<99991;i++)
    {

        if(record[i].point==maxpoint)
        {
            string ss=str[record[i].lastRound];
            int sum=0;
            int j;
            for( j=1;j<=n;j++)
            {
                if(str[j]==ss)
                {
                    sum+=pt[j];
                    if(sum>=maxpoint)
                    {
                        break;
                    }
    
                }
            }
            if(j<leastround)
                leastround=j;
        }
    }

    cout<<str[leastround]<<endl;
    return 0;
}

2B真是晕，感觉不是很难，dp部分比较简单，判断最后0的个数也就是USACO里提到过的，找2和5个数就完了，可是写出来vs报错stack overflow，但是我看我申请的空间还没以前做题用的大，贴个别人过了先.晕，这几天好忙，头都爆了

#include <cstdio>  
#include <cstring>  
#include <algorithm>  
#include <cmath>  
#include <iostream>  
#define maxn 1010  
#define inf 0xfffffff  
using namespace std;  
int tmp[maxn][maxn],five[maxn][maxn],two[maxn][maxn];  
int dp2[maxn][maxn],dp5[maxn][maxn];  
char dir2[maxn][maxn],dir5[maxn][maxn];  
int n;  
int get(int p,int n)  
{  
    if(n==0)  
        return 1;  
    int cnt=0;  
    while(n%p==0)  
    {  
        n/=p;  
        cnt++;  
    }  
    return cnt;  
}  
int zero_x,zero_y;  
bool flag;  
void print(char dir[][maxn],int x,int y)  
{  
    //cout<<x<<":"<<y<<endl;  
    if(x==1&&y==1)  
        return ;  
    if(dir[x][y]=='D')  
        print(dir,x-1,y);  
    else  
        print(dir,x,y-1);  
    printf("%c",dir[x][y]);  
}  
int main()  
{  
    scanf("%d",&n);  
    flag=true;  
    for(int i=1;i<=n;i++)  
        for(int j=1;j<=n;j++)  
        {  
            scanf("%d",&tmp[i][j]);  
            if(tmp[i][j])  
            {  
                two[i][j]=get(2,tmp[i][j]);  
                five[i][j]=get(5,tmp[i][j]);  
            }  
            else  
            {  
                flag=false;  
                zero_x=i;  
                zero_y=j;  
            }  
        }  
        memset(dp2,0,sizeof(dp2));  
        memset(dp5,0,sizeof(dp5));  
        for(int i=1;i<=n;i++)  
            for(int j=1;j<=n;j++)  
            {  
                if(tmp[i][j]==0)  
                {  
                    dp2[i][j]=inf;  
                }  
                else if(i==1&&j==1)  
                {  
                    dir2[i][j]=' ';  
                    dp2[i][j]=two[i][j];  
                }  
                else if(i==1)  
                {  
                    dp2[i][j]=dp2[i][j-1]+two[i][j];  
                    dir2[i][j]='R';  
                }  
                else if(j==1)  
                {  
                    dp2[i][j]=dp2[i-1][j]+two[i][j];  
                    dir2[i][j]='D';  
                }  
                else  
                {  
                    if(dp2[i-1][j]<dp2[i][j-1])  
                        dir2[i][j]='D';  
                    else  
                        dir2[i][j]='R';  
                    dp2[i][j]=min(dp2[i-1][j],dp2[i][j-1])+two[i][j];  
                }  
            }  
            for(int i=1;i<=n;i++)  
                for(int j=1;j<=n;j++)  
                {  
                    if(tmp[i][j]==0)  
                    {  
                        dp5[i][j]=inf;  
                    }  
                    else if(i==1&&j==1)  
                    {  
                        dir5[i][j]=' ';  
                        dp5[i][j]=five[i][j];  
                    }  
                    else if(j==1)  
                    {  
                        dir5[i][j]='D';  
                        dp5[i][j]=dp5[i-1][j]+five[i][j];  
                    }  
                    else if(i==1)  
                    {  
                        dir5[i][j]='R';  
                        dp5[i][j]=dp5[i][j-1]+five[i][j];  
                    }  
                    else  
                    {  
                        if(dp5[i-1][j]<dp5[i][j-1])  
                            dir5[i][j]='D';  
                        else  
                            dir5[i][j]='R';  
                        dp5[i][j]=min(dp5[i-1][j],dp5[i][j-1])+five[i][j];  
                    }  
                }  
                if(!flag)  
                {  
                    if(dp2[n][n]==0)  
                    {  
                        printf("0
");  
                        print(dir2,n,n);  
                    }  
                    else if(dp5[n][n]==0)  
                    {  
                        printf("0
");  
                        print(dir5,n,n);  
                    }  
                    else  
                    {  
                        printf("1
");  
                        for(int i=2;i<=zero_x;i++)  
                            printf("D");  
                        for(int j=2;j<=zero_y;j++)  
                            printf("R");  
                        for(int i=zero_x+1;i<=n;i++)  
                            printf("D");  
                        for(int j=zero_y+1;j<=n;j++)  
                            printf("R");  
                    }  
                }  
                else  
                {  
                    if(dp2[n][n]>dp5[n][n])  
                    {  
                        printf("%d
",dp5[n][n]);  
                        print(dir5,n,n);  
                    }  
                    else  
                    {  
                        printf("%d
",dp2[n][n]);  
                        print(dir2,n,n);  
                    }  
                }  
                printf("
");  
                return 0;  
}