牛客网 2018校招真题 爱奇艺 红和绿

Description

牛客网 2018校招真题 红和绿

Solving Ideas

题目没有要求涂染后’R’、'G’的数量要与涂染前一致，如"GGGGRRR"的最优解为"GGGGGGG"

以每个字符为中点，左边的涂成R，右边的涂成G，得到涂染个数，在多个涂染个数中取最小的。

Time complexity : O ( n 2 ) O(n^2) O(n2)

Space complexity : O ( 1 ) O(1) O(1)

Solution

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @author wylu
 */
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        char[] str = br.readLine().toCharArray();

        int res = Integer.MAX_VALUE, count;
        for (int i = 0; i < str.length; i++) {
            count = 0;
            for (int j = 0; j < i; j++) {
                if (str[j] != 'R') count++;
            }
            for (int j = i + 1; j < str.length; j++) {
                if (str[j] != 'G') count++;
            }
            res = Math.min(res, count);
        }
        System.out.println(res);
    }
}