10405 - Longest Common Subsequence

Problem C: Longest Common Subsequence

Sequence 1:

Sequence 2:


Given two sequences of characters, print thelength of the longest common subsequence of both sequences. Forexample, the longest common subsequence of the following twosequences:

abcdghaedfhr

is adh of length 3.

Input consists of pairs of lines. The first line of a pair containsthe first string and the second line contains the second string. Eachstring is on a separate line and consists of at most 1,000 characters

For each subsequent pair of input lines, output a line containing oneinteger number which satisfies the criteria stated above.

Sample input

a1b2c3d4ezz1yy2xx3ww4vvabcdghaedfhrabcdefghijklmnopqrstuvwxyza0b0c0d0e0f0g0h0i0j0k0l0m0n0o0p0q0r0s0t0u0v0w0x0y0z0abcdefghijklmnzyxwvutsrqpoopqrstuvwxyzabcdefghijklmn

Output for the sample input

432614

#include<stdio.h>#include<string.h>#define max(x,y) ((x)>(y)?(x):(y))char a[1005],b[1005];int f[1005][1005],i,j;int main(){while(gets(a)&&gets(b)){memset(f,0,sizeof(f));for(i=1;i<=strlen(a);i++)for(j=1;j<=strlen(b);j++)if(a[i-1]==b[j-1])f[i][j]=f[i-1][j-1]+1;elsef[i][j]=max(f[i-1][j],f[i][j-1]);printf("%d\n",f[strlen(a)][strlen(b)]);}return 0;}