Poj 1159

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题意; 5 Ab3bd 加上多少个字符可以是字符串为回文串 #include<iostream> using namespace std; short dp[5005][5005]; char s1[5005],s2[5005]; int fmax(int x,int y) {     if(x>y) return x;     return y; } int main() {     int n;     int i,j;     while(scanf("%d",&n)!=EOF)     {         scanf("%s",s1+1);         for(i=n;i>=1;i--)             s2[i]=s1[n-i+1];         memset(dp,0,sizeof(dp));         for(i=1;i<=n;i++)//s1的标号             for(j=1;j<=n;j++)//s2的标号             {                 if(s1[i]==s2[j])                     dp[i][j]=dp[i-1][j-1]+1;                 else                     dp[i][j]=fmax(dp[i-1][j],dp[i][j-1]);             }         printf("%d\n",n-dp[n][n]);     }     return 0; }