Leetcode P822 Java使用Set去解决此问题

首先把fronts 和 backs 相同下标并且值相同

HashSet set = new HashSet<>();
for (int i = 0; i < fronts.length; i++) {
    if (fronts[i] == backs[i]){
        set.add(fronts[i]);
    }
}

我们程序中可能翻转也可能不翻转，所以我们先找到正面的最小值

for (int front : fronts) {
    if (!set.contains(front)) {
        res = Math.min(res,front);
    }
}

假设翻转，是否能找到更小的值

for (int front : backs) {
    if (!set.contains(front)) {
        res = Math.min(res,front);
    }
}

package leccod;

import java.util.HashSet;

public class P822 {
    public static void main(String[] args) {

    }

    public int flipgame(int[] fronts, int[] backs) {
        HashSet set = new HashSet<>();
        for (int i = 0; i < fronts.length; i++) {
            if (fronts[i] == backs[i]){
                set.add(fronts[i]);
            }
        }
        int res = Integer.MAX_VALUE;

        for (int front : fronts) {
            if (!set.contains(front)) {
                res = Math.min(res,front);
            }
        }

        for (int front : backs) {
            if (!set.contains(front)) {
                res = Math.min(res,front);
            }
        }
        return res;
    }
}