有无序的实数列V[N],要求求里面大小相邻的实数的差的最大值,关键是要求线性空间和线性时间。

时间:2021-07-27 07:31:07
int findMaxDifBt2Nums(int* arr, int len) {
	int maxItem = arr[0], minItem = arr[0];
	for (int i = 1; i < len; ++i) {
		if (arr[i] > maxItem) {
			maxItem = arr[i];
		}
		if (arr[i] < minItem) {
			minItem = arr[i];
		}
	}

	//间距
	int bar = (maxItem - minItem) / (len - 1);
	int (*bucket)[2] = new int[len][2];
	memset(bucket, 0, sizeof(int) * len * 2);
	for (int i = 0; i < len; ++i) {
		int pos = (arr[i] - minItem) / bar;

		if (bucket[pos][0] == 0) {
			bucket[pos][0] = bucket[pos][1] = arr[i];
		} else {
			if (arr[i] > bucket[pos][1]) {
				bucket[pos][1] = arr[i];
			}
			if (arr[i] < bucket[pos][0]) {
				bucket[pos][0] = arr[i];
			}
		}
	}

	int maxDif = 0;
	int* tmp = NULL;
	for (int i = 1; i < len; ++i) {
		if (bucket[i][0] != 0) {
			if (!tmp) {
				tmp = bucket[i];
				continue;
			}
			maxDif = max(maxDif, bucket[i][0] - tmp[1]);
			tmp = bucket[i];
		}
	}

	delete[] bucket;
	return maxDif;
}