scanf和cin的比较

http://codeforces.com/contest/785/problem/A

一个简单的加法题，但是当你是用的是cin输入时时间是483ms而scanf时间被压缩到62ms

cin版

#include <iostream>
#include<bits/stdc++.h>
#include <malloc.h>
using namespace std;
//map<string,int>mp;
//char ch[5]={'T','C','O','D','I'};
//int ch1[5]={4,6,8,12,20};
int main()
{
    int n;
    string s;
    while(~scanf("%d",&n))
    {
        int ans=0;
        for(int i=0;i<n;i++)
        {
            cin>>s;
            if(s[0]=='T')
            ans+=4;
            else if(s[0]=='C')
                ans+=6;
            else if(s[0]=='O')
                ans+=8;
            else if(s[0]=='D')
                ans+=12;
            else if(s[0]=='I')
                ans+=20;
        }
        printf("%d
",ans);
    }
    return 0;
}

scanf版

#include <iostream>
#include<bits/stdc++.h>
#include <malloc.h>
using namespace std;
//map<string,int>mp;
//char ch[5]={'T','C','O','D','I'};
//int ch1[5]={4,6,8,12,20};
int main()
{
    int n;
    char s[100];
    while(~scanf("%d",&n))
    {
        int ans=0;
        for(int i=0;i<n;i++)
        {
            scanf("%s",s);
            if(s[0]=='T')
            ans+=4;
            else if(s[0]=='C')
                ans+=6;
            else if(s[0]=='O')
                ans+=8;
            else if(s[0]=='D')
                ans+=12;
            else if(s[0]=='I')
                ans+=20;
        }
        printf("%d
",ans);
    }
    return 0;
}