hdoj-1503 （LCS解的输出）

题目链接

回溯输出解

 #include <bits/stdc++.h>
 using namespace std;
 const int N=;
 int dp[N][N],dir[N][N];
 char s1[N],s2[N];
 int n1,n2;
 void m_printf (int x,int y) {
     if (x<=||y<=)  {
         for (int i=;i<=x;i++)
             putchar(s1[i]);
         for (int i=;i<=y;i++)
             putchar(s2[i]);
         return ;
     }
     if (dir[x][y]==) {
         m_printf(x-,y-);
         putchar (s1[x]);
     }
     else if (dir[x][y]>) {
         m_printf(x-,y);
         putchar (s1[x]);
     }
     else {
         m_printf(x,y-);
         putchar (s2[y]);
     }
     return ;
 }
 int main ()
 {
     while (~scanf (" %s %s",s1+,s2+)) {
         memset (dp,,sizeof(dp));
         int n1=strlen(s1+);
         int n2=strlen(s2+);
         for (int i=;i<=n1;i++)
             for (int j=;j<=n2;j++) {
                 if (s1[i]==s2[j]) {
                     dir[i][j]=;
                     dp[i][j]=dp[i-][j-]+;
                 }
                 else if  (dp[i-][j]>dp[i][j-]) {
                     dir[i][j]=;
                     dp[i][j]=dp[i-][j];
                 }
                 else {
                     dir[i][j]=-;
                     dp[i][j]=dp[i][j-];
                 }
             }
        // printf("%d\n",dp[n1][n2]);
         m_printf(n1,n2);
         printf("\n");
     }
     return ;
 }