UVa 10934 Dropping water balloons

UVa 10934 Dropping water balloons

题目链接：UVa 10934 Dropping water balloons

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Problem Description

It’s frosh week, and this year your friends have decided that they would initiate the new computer science students by dropping water balloons on them. They’ve filled up a large crate of identical water balloons, ready for the event. But as fate would have it, the balloons turned out to be rather tough, and can be dropped from a height of several stories without bursting! So your friends have sought you out for help. They plan to drop the balloons from a tall building on campus, but would like to spend as little effort as possible hauling their balloons up the stairs, so they would like to know the lowest floor from which they can drop the balloons so that they do burst.
You know the building has n floors,and your friends have given you k identical balloons which you may use (and break) during your trials to find their answer. Since you are also lazy, you would like to determine the minimum number of trials you must conduct in order to determine with absolute certainty the lowest floor from which you can drop a balloon so that it bursts (or in the worst case, that the balloons will not burst even when dropped from the top floor). A trial consists of dropping a balloon from a certain floor. If a balloon fails to burst for a trial, you can fetch it and use it again for another trial.

Input

The input consists of a number of test cases, one case per line. The data for one test case consists of two numbers k and n, 1 ≤ k ≤ 100 and a positive n that fits into a 64 bit integer (yes, it’s a very tall building). The last case has k = 0 and should not be processed.

Output

For each case of the input, print one line of output giving the minimum number of trials needed to solve the problem. If more than 63 trials are needed then print ‘More than 63 trials needed.’ instead of the number.

Sample Input

2 100
10 786599
4 786599
60 1844674407370955161
63 9223372036854775807
0 0

Sample Output

14
21
More than 63 trials needed.
61
63

题意：

你有k个一模一样的水球，在一个n层楼的建筑物上进行测试，你想知道水球最低从几层楼往下丢可以让水球破掉。由于你很懒，所以你想要丢最少次水球来测出水球刚好破掉的最低楼层。（在最糟情况下，水球在顶楼也不会破）你可以在某一层楼丢下水球来测试，如果水球没破，你可以再捡起来继续用。

AC代码：

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <iostream>
#include <locale>
#include <vector>
#include <string>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <functional>

using namespace std;

long long dp[65][65];

long long min(long long x,long long y)
{
    return x<y;
}

void f()
{
    memset(dp,0,sizeof dp);
    for(int i=1; i<64; i++)
        for(int j=1; j<64; j++)
            dp[i][j]=dp[i-1][j-1]+dp[i][j-1]+1;
}

int main()
{
    f();
    int k;
    long long n;
    while(~scanf("%d%lld",&k,&n),k)
    {
        int flag=1;
        k=min(63,k);
        for(int i=0;i<=63;i++)
        {
            if(dp[k][i]>=n)
            {
                flag=0;
                printf("%d\n",i);
                break;
            }
        }
        if(flag)
            printf("More than 63 trials needed.\n");
    }
    return 0;
}