package top100liked

import "testing"

// https://leetcode.cn/problems/minimum-window-substring/?envType=study-plan-v2&envId=top-100-liked

func minWindow(s string, t string) string {
	if len(t) > len(s) {
		return ""
	}
	need := make(map[byte]int)
	for _, v := range []byte(t) {
		need[v]++
	}

	window := make(map[byte]int)
	valid := 0
	left := 0
	minLen := len(s) + 1
	start := 0

	for right := 0; right < len(s); right++ {
		ch := s[right]
		if _, ok := need[ch]; ok {
			window[ch]++
			if window[ch] == need[ch] {
				valid++
			}
		}

		for valid == len(need) {
			if right-left+1 < minLen {
				minLen = right - left + 1
				start = left
			}

			d := s[left]
			left++
			if _, ok := need[d]; ok {
				if window[d] == need[d] {
					valid--
				}
				window[d]--
			}
		}
	}

	if minLen == len(s)+1 {
		return ""
	}

	return s[start : start+minLen]
}

func TestS12(t *testing.T) {
	println(minWindow("ADOBECODEBANC", "ABC"))
	println(minWindow("a", "a"))
	println(minWindow("a", "aa"))
}