2/17总结--归并排序+哈希还有一道思维题

 C - 简单 --- C - Make it Simplehttps://atcoder.jp/contests/abc393/tasks/abc393_c?lang=en

 

归并排序+hash哈希   哈希计算有效对一一对应

方法一()

#define _CRT_SECURE_NO_WARNINGS  
#include<bits/stdc++.h>
//定义
using namespace std;
int n, m, k, d[500002];
struct da {
	int x, y;
}q[500005],t[500005];

//归并
void merge(da q[], da temp[], int low, int high) {
	if (low >= high) return;
	int mid = low + (high - low) / 2;
	merge(q, temp, low, mid);
	merge(q, temp, mid + 1, high);
	int i = low, j = mid + 1, k = low;
	while (i <= mid && j <= high) {
		if (q[i].x < q[j].x)temp[k++] = q[i++];
		else temp[k++] = q[j++];
	}
	while (i <= mid)temp[k++] = q[i++];
	while (j <= high)temp[k++] = q[j++];
	for (int i = low; i <= high; i++)q[i] = temp[i];
}

int main() {
    //输入
	scanf("%d %d", &n, &m);
	int j = 1;
	for (int i = 1; i <= m; i++) {
		scanf("%d %d", &q[j].x, &q[j].y);
		//我要求x[i]<y[i]
		if (q[j].x > q[j].y) {
			int temp = q[j].x;
			q[j].x = q[j].y;
			q[j].y = temp;
			j++;
		}
		else if (q[j].x == q[j].y) {
			k++;
			if (i == m)j++;
		}
		else {
			j++;
		}
	}
	j--;
	//排完序
	merge(q, t, 1, j);
    //hash哈希
	for (int i = 1; i <= j; i++) {
		if (d[q[i].y] != q[i].x) {
			d[q[i].y] = q[i].x;
		}
		else {
			k++;
		}
	}
	printf("%d\n", k);
	return 0;
}

方法一(简化版)

#define _CRT_SECURE_NO_WARNINGS  
#include<bits/stdc++.h>

using namespace std;
int n, m, k, d[500002];
struct da {
	int x, y;
}q[500005],t[500005];
//归并
void merge(da q[], da temp[], int low, int high) {
	if (low >= high) return;
	int mid = low + (high - low) / 2;
	merge(q, temp, low, mid);
	merge(q, temp, mid + 1, high);
	int i = low, j = mid + 1, k = low;
	while (i <= mid && j <= high) {
		if (q[i].x < q[j].x)temp[k++] = q[i++];
		else temp[k++] = q[j++];
	}
	while (i <= mid)temp[k++] = q[i++];
	while (j <= high)temp[k++] = q[j++];
	for (int i = low; i <= high; i++)q[i] = temp[i];
}

int main() {
	scanf("%d %d", &n, &m);
	for (int i = 1; i <= m; i++) {
		scanf("%d %d", &q[i].x, &q[i].y);
		//我要求x[i]<y[i]
		if (q[i].x > q[i].y) {
			int temp = q[i].x;
			q[i].x = q[i].y;
			q[i].y = temp;
		}
		else if (q[i].x == q[i].y) {
			k++;
			i--;
			m--;
		}
	}
	//排完序
	merge(q, t, 1, m);
    //哈希
	for (int i = 1; i <= m; i++) {
		if (d[q[i].y] != q[i].x) {
			d[q[i].y] = q[i].x;
		}
		else {
			k++;
		}
	}
	printf("%d\n", k);
	return 0;
}

方法二(这个归并是我哥们写的)

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int n, m, x, y,sum=0;
struct s {
	int x;
	int y;
}a[5000009],e[5000009];
int b[5000009];
void digui(int i, int j) {
	if (i >= j) {
		return;
	}
	int mid = i + (j - i) / 2;
	digui(i, mid);
	digui(mid + 1, j);
	int r = i, l = mid + 1, h = i;
	while (r <= mid && l <= j) {
		if (a[r].x < a[l].x) {
			e[h].x = a[r].x;
			e[h].y = a[r].y;
			h++;
			r++;
		}
		else {
			e[h].x = a[l].x;
			e[h].y = a[l].y;
			h++;
			l++;
		}
	}
	while (r <= mid) {
		e[h].x = a[r].x;
		e[h].y = a[r].y;
		h++;
		r++;
	}
	while (l <= j) {
		e[h].x = a[l].x;
		e[h].y = a[l].y;
		h++;
		l++;
	}
	h = i;
	while (h <= j) {
		a[h].x = e[h].x;
		a[h].y = e[h].y;
		h++;
	}
}
int main() {
	scanf("%d %d", &n, &m);
	int j = 0;
	for (int i = 0;i < m;i++) {
		scanf("%d %d", &x, &y);
		if (x == y) {
			sum++;
		}
		else if (x > y) {
			a[j].x = y;
			a[j].y = x;
			j++;
		}
		else {
			a[j].x = x;
			a[j].y = y;
			j++;
		}
	}
	digui(0, j - 1);
	for (int i = 0;i < j;i++) {
		if (b[a[i].y] != a[i].x) {
			b[a[i].y] = a[i].x;
		}
		else {
			sum++;
		}
	}
	printf("%d\n", sum);
	return 0;
}

codeforces.com/problemset/problem/2067/A

当时写题的时候以为这题很难,结果很简单,wokao, 可能是测试数据太假了,被吓到了

#include <iostream>
using namespace std;

int main() {
    int t;
    cin >> t; // 读取测试用例的数量

    while (t--) {
        int x, y;
        cin >> x >> y; // 对于每个测试用例，读取两个整数x和y
        int l = 0; // l用于标记是否满足条件，0表示不满足，1表示满足

        // 检查y是否等于x加1
        if (y == 1 + x) l = 1;
        // 检查y是否小于x，并且x和y的差是9的倍数
        else if ((1 + x - y) % 9 == 0 && x > y) l = 1;

        // 如果l为1，则输出"yes"，表示满足条件
        if (l) cout << "yes" << endl;
        // 如果l为0，则输出"no"，表示不满足条件
        else cout << "no" << endl; 
    }

    return 0;
}

Задача - 2065B - Codeforces --- Задача - 2065B - Codeforces

#include<bits/stdc++.h>
using namespace std;
int main() {
	int t; cin >> t;
	while (t--) {
		string s;
		cin >> s;
		int count = 0;
		for (int i = s.size() - 1; i >= 1; i--) {
			if (s[i] == s[i - 1]) {
				count = i; break;
			}
		}
		int l = s.size();
		if (count != 0)cout << 1 << endl;
		else {
			cout << l << endl;
		}
	}
	return 0;
}

看到这里的大佬好,我水一下