383.判断一个字符串是否能够包含另外一个字符串 Ransom Note

Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.

Each letter in the magazine string can only be used once in your ransom note.

Note:
You may assume that both strings contain only lowercase letters.

canConstruct("a", "b") -> false
canConstruct("aa", "ab") -> false
canConstruct("aa", "aab") -> true

static public bool CanConstruct(string ransomNote, string magazine) {
	Dictionary<char, int> d = new Dictionary<char, int>();
	char[] mArr = magazine.ToCharArray();
	int mArrLength = mArr.Length;
	for (int i = 0; i < mArrLength; i++) {
		char c = mArr[i];
		int v = 0;
		if (d.TryGetValue(c, out v)) {
			d[c] = v + 1;
		} else {
			d.Add(c, 1);
		}
	}
	char[] rArr = ransomNote.ToCharArray();
	int rArrLength = rArr.Length;
	for (int i = 0; i < rArrLength; i++) {
		char c = rArr[i];
		int v = 0;
		if (!d.TryGetValue(c, out v) || v == 0) {
			return false;
		} else {
			d[c] -= 1;
		}
	}
	return true;
}

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