美团点评2020校招前端方向笔试题

五：斐波那契数列

代码

#include <iostream>
#include <cstring>

using namespace std;
typedef long long ll;
const int N = 10010;
ll a[N];
int n;

int main()
{
    
    
	cin >> n;
	a[1] = 1;
	a[2] = 1;
	for(int i = 3; i <= n + 1; i++)
	{
    
    
		a[i] = a[i - 1] + a[i - 2];
	//	cout << i << " " << a[i] << endl;
	}
	
	cout << a[n + 1] << endl;
	
	return 0;
 } 

六：代金券组合
搜索写法（40%）
代码

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
typedef long long ll;
const int N = 10010;
int a[N];
int n, p;
int ans = 0x3f3f3f3f;
bool f;

void dfs(int r, int num)
{
    
    
	if(num >= ans) return;
	if(r == 0)
	{
    
    
		ans = min(ans, num);
	}
	if(r < 0) 
		return;
	
	for(int i = 1; i <= n; i++)
	{
    
    
		dfs(r - a[i], num + 1);
	}
	return;
}

int main()
{
    
    
	while(cin >> p && p)
	{
    
    
        f = false;
		cin >> n;
		for(int i = 1; i <= n; i++)
			cin >> a[i];
		sort(a + 1, a + n + 1);
		reverse(a + 1, a + 1 + n);
		dfs(p, 0);
	}
	cout <<ans << endl;
	return 0;
 } 

DP代码 完全背包

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
typedef long long ll;
const int N = 10010;
int a[N];
int n, p;
int f[N];

int main()
{
    
    
	while(cin >> p && p)
	{
    
    
		cin >> n;
		for(int i = 1; i <= n; i++)
			cin >> a[i];
		memset(f, 0x3f, sizeof f);
		f[0] = 0;
		for(int i = 1; i <= n; i++)
			for(int j = a[i]; j <= p; j++)
			{
    
    
					f[j] = min(f[j], f[j - a[i]] + 1);
			}
	
		if(f[p] > 0x3f3f3f3f / 2)
			cout << "Impossible" << endl;
		else cout << f[p] << endl;
	}

	return 0;
 } 

七：迷宫寻路

代码

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
typedef long long ll;
const int N = 110;
int a[N][N];
int f[N][N];

int n, m;

int main()
{
    
    
	cin >> n >> m;
	for(int i = 1; i <= n; i++)
		for(int j = 1; j <= m; j++)
			cin >>a[i][j];
	
	memset(f, 0x3f, sizeof f);
	f[1][1] = a[1][1];
	for(int i = 1; i <= n; i++)
		for(int j = 1; j <= m; j++)
		{
    
    
			if(i == 1 && j == 1) continue;
			f[i][j] = min(f[i - 1][j], f[i][j - 1]);
			f[i][j] += a[i][j];
		}
		
	cout << f[n][m] << endl;

	return 0;
 } 

八：星际穿越
代码

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

typedef long long ll;

int a[10][10][10];
bool vis[10][10][10];
int n;
int xx, yy, zz, maxx = 0;
int ans = 0;

void dfs(int x, int y, int z, int num)
{
    
    
	ans = max(ans, num);

	int fx = x - 1;
	int fy = y;
	int fz = z;
	if (fx >= 0 && fx < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
	fx = x + 1;
	fy = y;
	fz = z;
	if (fx >= 0 && fx < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
	fx = x;
	fy = y - 1;
	fz = z;
	if (fy >= 0 && fy < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
	fx = x;
	fy = y + 1;
	fz = z;
	if (fy >= 0 && fy < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
	fx = x;
	fy = y;
	fz = z - 1;
	if (fz >= 0 && fz < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
	fx = x;
	fy = y;
	fz = z + 1;
	if (fz >= 0 && fz < n && !vis[fx][fy][fz] && a[fx][fy][fz] < a[x][y][z])
	{
    
    
		vis[fx][fy][fz] = true;
		dfs(fx, fy, fz, num + a[fx][fy][fz]);
		vis[fx][fy][fz] = false;
	}
}

int main()
{
    
    

	cin >> n;
	for (int i = 1; i <= n * n * n; i++)
	{
    
    
		int x, y, z;
		cin >> x >> y >> z;
		int p;
		cin >> p;
		a[x][y][z] = p;

		if (p > maxx)
		{
    
    
			xx = x;
			yy = y;
			zz = z;
			maxx = p;
		}
	}
	vis[xx][yy][zz] = true;
	dfs(xx, yy, zz, maxx);
	cout << ans << endl;
	return 0;
}