POJ1458(Common Subsequence)

题目链接

经典DP问题。由于最初if(c[i][j]>=0)   return c[i][j];一句中少写一个等于号造成TLE，查了好久啊……

View Code

 1 #include <stdio.h>
 2 #include <string.h>
 3 #define MAX(a,b) ((a)>(b)?(a):(b))
 4 #define N 300
 5 char a[N],b[N];
 6 int c[N][N];
 7 int f(int i,int j)
 8 {
 9     if(i<0 || j<0)  return 0;
10     if(c[i][j]>=0)   return c[i][j];
11     if(a[i]==b[j])  return c[i][j]=f(i-1,j-1)+1;
12     return c[i][j]=MAX(f(i-1,j),f(i,j-1));
13 }
14 int main()
15 {
16     int i,j;
17     while(~scanf("%s%s",a,b))
18     {
19         memset(c,-1,sizeof(c));
20         i=strlen(a),j=strlen(b);
21         printf("%d\n",f(i-1,j-1));
22     }
23     return 0;
24 }