Codeforces 1065C Make It Equal(差分+贪心)

Posted 2021-01-12 wrjlinkkkkkk

题意：n个塔，第i个塔由$h_i$个cube组成，每次可以切去某高度h以上的最多k个cube，问你最少切多少次，可以让所有塔高度相等

k>=n, n<=2e5

思路：差分统计每个高度i有的方块数nh[i]，然后从高到低贪心的切就行了

代码：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<string>
//#include<stack>
#include<queue>
#include<deque>
#include<set>
#include<vector>
#include<map>
#include<functional>
    
#define fst first
#define sc second
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define lson l,mid,root<<1
#define rson mid+1,r,root<<1|1
#define lc root<<1
#define rc root<<1|1
#define lowbit(x) ((x)&(-x)) 

using namespace std;

typedef double db;
typedef long double ldb;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> PI;
typedef pair<ll,ll> PLL;

const db eps = 1e-6;
const int mod = 100003;
const int maxn = 2e5+100;
const int maxm = 2e5+100;
const ll inf = 0x3f3f3f3f3f3f3f3f;
const db pi = acos(-1.0);

int nh[maxn];
int main() {
    int n;ll m;
    scanf("%d %lld", &n, &m);
    int vol = 0;
    for(int i = 1; i <= n; i++){
        int c;
        scanf("%d", &c);
        nh[0]++;nh[c+1]--;
        
    }
    for(int i = 1; i <= maxn; i++){
        nh[i]+=nh[i-1];
    }
    int tmp = 0;
    int ans = 0;
    for(int i = maxn; i >= 0; i--){
        if(nh[i]==n)break;
        if(tmp+nh[i]>m){
            tmp=nh[i];
            ans++;
        }
        else tmp+=nh[i];
    }
    if(tmp>0)ans++;
    printf("%d", ans);
    return 0;
}