排序板子

针对cpp

选择排序

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for (LL i = 0; i < n - 1; i++) {
	for (LL j = i + 1; j < n; j++) {
		if (a[i] > a[j]) swap(a[i], a[j]);
	}
}

冒泡排序

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for (LL i = 0; i < n - 1; i++) {
	for (LL j = 0; j < n - i - 1; j++) {
		if (a[j] > a[j + 1]) swap(a[j], a[j + 1]);
	}
}

STL

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sort(a, a + n);

快速排序

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void quick_sort(LL q[], LL l, LL r) {
	if (l >= r) return;
	
	LL i = l - 1, j = r + 1, x = q[l + (r - l) / 2];
	while (i < j) {
		while (q[++i] < x);
		while (q[--j] > x);
		if (i < j) swap(q[i], q[j]);
	}
	
	quick_sort(q, l, j); quick_sort(q, j + 1, r);
}

归并排序

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void merge_sort(LL q[], LL l, LL r) {
	if (l >= r) return;
	
	LL mid = l + (r - l) / 2;
	merge_sort(q, l, mid);
	merge_sort(q, mid + 1, r);
	
	LL k = 0, i = l, j = mid + 1;
	while (i <= mid && j <= r) {
		if (q[i] <= q[j]) temp[k++] = q[i++];
		else temp[k++] = q[j++];
	}
	
	while (i <= mid) temp[k++] = q[i++];
	while (j <= r) temp[k++] = q[j++];
	
	for (i = l, j = 0; i <= r; i++, j++) q[i] = temp[j];
}

完整程序

OJ平台

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#include <bits/stdc++.h>
using namespace std;
typedef long long LL;

LL n, a[100010];

void quick_sort(LL q[], LL l, LL r) {
	if (l >= r) return;
	
	LL i = l - 1, j = r + 1, x = q[l + (r - l) / 2];
	while (i < j) {
		while (q[++i] < x);
		while (q[--j] > x);
		if (i < j) swap(q[i], q[j]);
	}
	
	quick_sort(q, l, j); quick_sort(q, j + 1, r);
}

LL temp[100010];

void merge_sort(LL q[], LL l, LL r) {
	if (l >= r) return;
	
	LL mid = l + (r - l) / 2;
	merge_sort(q, l, mid);
	merge_sort(q, mid + 1, r);
	
	LL k = 0, i = l, j = mid + 1;
	while (i <= mid && j <= r) {
		if (q[i] <= q[j]) temp[k++] = q[i++];
		else temp[k++] = q[j++];
	}
	
	while (i <= mid) temp[k++] = q[i++];
	while (j <= r) temp[k++] = q[j++];
	
	for (i = l, j = 0; i <= r; i++, j++) q[i] = temp[j];
}

int main() {
	cin >> n;
	for (LL i = 0; i < n; i++)
		scanf("%lld", &a[i]);
	
	// 排序实现
	
//	// 选择排序
//	for (LL i = 0; i < n - 1; i++) {
//		for (LL j = i + 1; j < n; j++) {
//			if (a[i] > a[j]) swap(a[i], a[j]);
//		}
//	}
	
//	// 冒泡排序
//	for (LL i = 0; i < n - 1; i++) {
//		for (LL j = 0; j < n - i - 1; j++) {
//			if (a[j] > a[j + 1]) swap(a[j], a[j + 1]);
//		}
//	}

//	// stl
//	sort(a, a + n);
	
	// 快速排序
	quick_sort(a, 0, n - 1);
	
	// 归并排序
	merge_sort(a, 0, n - 1);
	
	
	for (LL i = 0; i < n; i++)
		printf("%lld ", a[i]);

	return 0;
}