2767. 将字符串分割为最少的美丽子字符串

2767. 将字符串分割为最少的美丽子字符串

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Java:

class Solution {
    int cnt;
    int ans;
    int[] arr;
    Set<Integer> set;

    private void dfs(String s, String s1, int pos, int len) {
        if (pos == len) {
            ans = Math.min(ans, cnt);
            return;
        }
        for(int i = pos; i < len; ++i) {
            String s2 = s.substring(pos, i + 1);
            int num = Integer.parseInt(s2, 2);
            if (!s2.startsWith("0") && set.contains(num)) {  //"101101111101" 防止 01111101，题意要求全部分隔
                ++cnt;
                dfs(s, s2, i + 1, len);
                --cnt;
            }
        }
    }

    public int minimumBeautifulSubstrings(String s) {
        cnt = 0;
        ans = Integer.MAX_VALUE;
        arr = new int[]{1, 5, 25, 125, 625, 3125, 15625, 78125};
        set = new HashSet<>();
        for(int a : arr) {
            set.add(a);
        }

        dfs(s, "0", 0, s.length());
        return ans == Integer.MAX_VALUE ? -1 : ans;
    }
}