第十四届蓝桥杯集训——练习解题阶段(无序阶段)-ALGO-122 未名湖边的烦恼

#include<stdio.h>

int function(int m,int n)
{
//	printf("%d%d",m,n);
	if(m<n)
		return 0;
	if(m==0||n==0)
	{
		return 1;
	}
	else
	{
		return function(m-1,n)+function(m,n-1);
	
	} 
	
	return 0;
}
int main()
{
	int n,m,sum=0;
	scanf("%d%d",&m,&n);
	sum+=function(m,n);
	printf("%d",sum);
	return 0;
} 

#include <iostream>

using namespace std;

void fun(int m, int n, int temp, int &count);

int main(void)
{
	int m, n, count;

	while (scanf("%d %d", &m, &n) == 2)
	{
		count = 0;
		fun(m, n, 0, count);
		printf("%d\n", count);
	}


	return 0;
}

void fun(int m, int n, int temp, int &count)
{
	if (!(m || n))
	{
		count++;
	}
	else
	{
		if (temp)
		{
			if (m >= 1)
			{
				fun(m-1, n, temp+1, count);
			}

			if (n >= 1)
			{
				fun(m, n-1, temp-1, count);
			}
		}
		else
		{
			if (m >= 1)
			{
				fun(m-1, n, temp+1, count);
			}
		}
	}
}

import java.util.*;
import java.io.IOException;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Main {
	public static final int maxn = (int)(1e3 + 5);
	public static final int maxm = (int)(1e6 + 5);
	public static long C(int a, int b) {
		if (b < 0 || b > a) return 0;
		long ret = 1;
		for (int i = 1; i <= b; ++i) {
			ret *= (long)(a - i + 1);
			ret /= (long)i;
		}
		return ret;
	}
	public static void main(String[] args) {
		InputStream inputStream = System.in;
        InputReader in = new InputReader(inputStream);
        int m = in.nextInt();
        int n = in.nextInt();
        if (m < n) {
        	System.out.println(0);
        } else {
        	System.out.println(C(n + m, n) - C(n + m, n - 1));
        }
    }
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
        public String next() {
            while(tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}

m, n = map(int, input().split())
data = [[0 for i in range(n + 1)] for j in range(m + 1)]
for i in range(1, m + 1):
    data[i][0] = 1
    for j in range(1, n + 1):
        if i >= j:
            data[i][j] = data[i - 1][j] + data[i][j - 1]
print(data[m][n])