URAL 2024 Adventure Time 思维题、Interesting

A - Adventure Time

Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u

Submit Status Practice URAL 2024

Description

‘Here’s for you!’ shouted Finn fighting the Shadow Guardians. ‘Jake! Collect the Darkness Rocks and let’s run from here!’

Jake would have been glad to finish as soon as possible, because it was wet and sad in the Dangerous Cave, but it was not so easy to 

gather Rocks. So he called BMO and asked him to help with choosing an optimal set of Rocks. Jake told BMO that there were n Rocks 

in the Cave, and they were numbered with different integers from 1 to  n. Each Rock was painted one of 26 colors. Jake also reminded BMO of Princess Bubblegum’s warning: there should be at most k Rocks of pairwise different colors among the Rocks taken from 

the Cave. Only a set of Rocks with this property is safe. If one takes an unsafe set of Rocks from the Cave, Cosmic Evil will be awakened! Of course, Jake doesn’t want to awaken the Evil, but he wants to take as many Darkness Rocks from the Cave as possible. 

Help BMO to find the size of the largest safe set of Rocks and the number of different safe sets of this size. Two sets of Rocks are different if one of them contains a Rock with a number that is not contained in the other set.

Input

The first line contains n lowercase English letters (1 ≤ n ≤ 10 ⁵); each letter denotes the color of a Rock. In the second line you are 

given the integer k (1 ≤ k ≤ 26).

Output

Output two integers separated with a space: the size of the largest safe set of Darkness Rocks and the number of different safe sets of 

this size.

Sample Input

inputoutput

abcde1

1 5

ababac2

5 1

Source

UESTC 2016 Summer Training #17 Div.2

URAL 2024

My Solution

统计每个字母出现的次数， 然后从大到小排序

最大的k的总个数就是 he size of the largest safe set of Darkness Rocks 

然后1）如果color[k-1] != 0, 则 统计这k个里的 color[i] ==  color[k-1] 记为cnt1, 并统计所有的里面的color[i] == color[k-1] 记为 cnt2， 然后C[cnt2][cnt1]就是the number of different safe sets of this size.了

2）否则直接就是答案

复杂度 O(n)

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long LL;const int maxn = 1e5 + 8;char val[maxn];LL color[26], C[maxn][30];inline bool cmp(LL a, LL b){    return a > b;}int main(){    memset(C, 0, sizeof C);    for(int i = 0; i <= 26; i++){        C[i][0] = 1;        for(int j = 1; j <= i; j++){            C[i][j] = C[i-1][j-1] + C[i-1][j];        }    }    #ifdef LOCAL    freopen("a.txt", "r", stdin);    //freopen("b.txt", "w", stdout);    int T = 3;    while(T--){    #endif // LOCAL    memset(color, 0, sizeof color);    LL sz = 0, num = 1, k;    scanf("%s", val);    scanf("%I64d", &k);    int len = strlen(val);    for(int i = 0; i < len; i++)        color[val[i] - 'a']++;    sort(color, color + 26, cmp);    int cnt1 = 0, cnt2 = 0;    for(int i = 0; i < k; i++){        sz += color[i];        if(color[k-1] !=0 && color[i] == color[k-1]) cnt1++;    }    for(int i = 0; i < 26; i++){        if(color[k-1] != 0 && color[i] == color[k-1]) cnt2++;    }    if(color[k-1] != 0){        num = C[cnt2][cnt1];    }    printf("%I64d %I64d", sz, num);    #ifdef LOCAL    printf("\n");    }    #endif // LOCAL    return 0;}

  Thank you!

                                                                                                                                               ------from ProLights