583. Delete Operation for Two Strings

Given two words word1 and word2, find the minimum number of steps required to make word1 and word2 the same, where in each step you can delete one character in either string.

Example 1:

Input: "sea", "eat"
Output: 2
Explanation: You need one step to make "sea" to "ea" and another step to make "eat" to "ea".

Note:

The length of given words won't exceed 500.
Characters in given words can only be lower-case letters.
此题可理解为寻找公共最长子序列问题，使用动态规划的方法容易解决
class Solution
{
public:
int minDistance(string word1, string word2)
{
int n1,n2;
n1=word1.size();
n2=word2.size();
int c[n1+1][n2+1];
for(int i=0;i<n1+1;i++) c[i][0]=0;
for(int i=0;i<n2+1;i++) c[0][i]=0;
for(int i=1;i<=n1;i++)
{
for(int j=1;j<=n2;j++)
{
if(word1[i-1]==word2[j-1]) c[i][j]=c[i-1][j-1]+1;
else c[i][j]=max(c[i-1][j],c[i][j-1]);
}
}
int len=0;
for(int i=1;i<=n1;i++)
{
for(int j=1;j<=n2;j++)
{
if(c[i][j]>len) len=c[i][j];
}
}
return n1-len+n2-len;
}
};