題目連結

解題思路：
DP

提交程式碼：

class Solution {
    public int minDistance(String word1, String word2) {
        int[][] dp=new int[word2.length()+1][word1.length()+1];
        dp[0][0]=0;
        for(int i=0;i<word1.length();i++)
        	dp[0][i+1]=i+1;
        for(int i=0;i<word2.length();
 
i++)
        	dp[i+1][0]=i+1;
        
        for(int i=0;i<word2.length();i++) {
        	for(int j=0;j<word1.length();j++) {
        		if(word1.charAt(j)==word2.charAt(i))
        			dp[i+1][j+1]=minValue(dp[i][j],dp[i+1][j]+1,dp[i][j+1]+1);
        		else
				dp[i+1][j+1]=minValue(dp[i][j+1],
 
dp[i+1][j],dp[i][j])+1;
        	}
        }
        return dp[word2.length()][word1.length()];
    }
    
    public int minValue(int num1,int num2,int num3) {
    	if(num1>num2)
    		num1=num2;
    	if(num1>num3)
    		num1=num3;
    	return num1;
    }
}

執行結果：