上面0分下面AC，输入格式搞心态啊

#include <stdio.h>
#define maxn 1000010
int main()
{
    char ch;
    int i,max,b[maxn];
    i=0;
    for (int j=1;j<=maxn;j++) 
        b[j]=0;
    while (1){
        scanf("%c",&ch);
        if (ch!='G'&&ch!='R') break; 
        i++;
        if (ch=='G') b[i]=1;
        else if (ch=='R') b[i]=-1;
        b[i]+=b[i-1];
    }
    max=0;
    //for (int j=1;j<=i;j++) printf("%d ",b[j]);
    //printf("\n");
    for (int j=0;j<i;j++){
       if (max>i-j) break;
       for (int k=i;k>j;k--)
       if (b[k]==b[j]&&k-j>max) {max=k-j;break;} 
    }
    printf("%d\n",max);
}

#include <stdio.h>
#include <string.h>
#define maxn 100010
int main()
{
    char ch;
    int n,max,b[maxn];
    char s[100010];
    for (int j=1;j<=maxn;j++) 
        b[j]=0;
    scanf("%s",s);
    n=strlen(s);
     for (int i=1;i<=n;i++){
        if (s[i-1]=='G') b[i]=1;
        else b[i]=-1;
        b[i]+=b[i-1];
    }
    max=0;
    //for (int j=1;j<=i;j++) printf("%d ",b[j]);
    //printf("\n");
    for (int j=0;j<n;j++){
       if (max>n-j) break;
       for (int k=n;k>j;k--)
       if (b[k]==b[j]&&k-j>max) {max=k-j;break;} 
    }
    printf("%d\n",max);
}