805 B. 3-palindrome http://codeforces.com/problemset/problem/805/B

/*
題意字符串中不能有長度為三的回文串，且c數量最少
*/
#include<iostream>
#include<cstdio>
#include<cstring>

using namespace std;
char s[4]={‘a‘,‘a‘,‘b‘,‘b‘};
int n;

int main()
{
    scanf("%d",&n);
    for(int i=0;i<n;i++)
      printf(
 
"%c",s[i%4]);
    printf("\n");
    return 0;
}

807 A Is it rated? http://codeforces.com/problemset/problem/807/A

#include<iostream>
#include<cstdio>
#include<cstring>

#define maxn 1001

using namespace std;

int n,m,cnt;
int a[maxn],b[maxn];

inline int
 
 init()
{
    int x=0,f=1;char c=getchar();
    while(c>‘9‘||c<‘0‘){if(c==‘-‘)f=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘;c=getchar();}
    return x*f;
}

int main()
{
    n=init();
    for(int i=1;i<=n;i++)
    {
        a[i]=init();b[i]=init();
    }
    
 
for(int i=2;i<=n;i++)
    {
        if(a[i]!=b[i])
        {
            printf("rated\n");
            return 0;
        }
        if(a[i]>a[i-1])
        {
            printf("unrated\n");
            return 0;
        }
    }
    printf("maybe\n");
    return 0;
}

錯誤代碼

#include<iostream>
#include<cstdio>
#include<cstring>

#define maxn 1001

using namespace std;

int n,m,cnt;
int a[maxn],b[maxn];

inline int init()
{
    int x=0,f=1;char c=getchar();
    while(c>‘9‘||c<‘0‘){if(c==‘-‘)f=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘;c=getchar();}
    return x*f;
}

int main()
{
    n=init();
    for(int i=1;i<=n;i++)
    {
        a[i]=init();b[i]=init();
    }
    for(int i=2;i<=n;i++)
    {
        if(a[i]!=b[i])//這裏！！可能第一個就不相同
        {
            printf("rated\n");
            return 0;
        }
        if(a[i]>a[i-1])
        {
            printf("unrated\n");
            return 0;
        }
    }
    printf("maybe\n");
    return 0;
}

codeforces——模擬