Codeforces Round #374 (Div. 2) D. Maxim and Array

传送门

分析：其实没什么好分析的。统计一下负数个数。如果负数个数是偶数的话，就要尽量增加负数或者减少负数。是奇数的话就努力增大每个数的绝对值。用一个优先队列搞一下就行了。 我感觉这道题的细节极为多，非常复杂，其实是自己智障了。。

我看了一下学长菊苣的代码，好精巧。。。注释部分是他的代码

/*****************************************************/
//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <map>
#include <set>
#include <ctime>
#include <stack>
#include <queue>
#include <cmath>
#include <string>
#include <vector>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <sstream>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
#define   offcin        ios::sync_with_stdio(false)
#define   sigma_size    26
#define   lson          l,m,v<<1
#define   rson          m+1,r,v<<1|1
#define   slch          v<<1
#define   srch          v<<1|1
#define   sgetmid       int m = (l+r)>>1
#define   LL            long long
#define   ull           unsigned long long
#define   mem(x,v)      memset(x,v,sizeof(x))
#define   lowbit(x)     (x&-x)
#define   bits(a)       __builtin_popcount(a)
#define   mk            make_pair
#define   pb            push_back
#define   fi            first
#define   se            second

const int    INF    = 0x3f3f3f3f;
const LL     INFF   = 1e18;
const double pi     = acos(-1.0);
const double inf    = 1e18;
const double eps    = 1e-9;
const LL     mod    = 1e9+7;
const int    maxmat = 10;
const ull    BASE   = 31;

/*****************************************************/

const int maxn = 2e5 + 5;
struct Node {
    LL pos, val;
}node[maxn];
struct kk {
    LL pos, val;
    bool operator <(const kk &rhs) const {
        return abs(val) > abs(rhs.val);
    }
};
priority_queue<kk> q;
int N, k, x;
bool cmp1(const Node &a, const Node &b) {return a.val < b.val; }
bool cmp2(const Node &a, const Node &b) {return a.pos < b.pos; }
int main(int argc, char const *argv[]) {
    cin>>N>>k>>x;
    int neg = 0;
    int flag = 1;
    for (int i = 0; i < N; i ++) {
        cin>>node[i].val;
        node[i].pos = i;
        if (node[i].val < 0) neg ++;
    }
    sort(node, node + N, cmp1);
    if (neg && (neg & 1) == 0) {
        int lb = 0, ub = N - 1, res = -1;
        while (lb <= ub) {
            int mid = (lb + ub) >> 1;
            if (node[mid].val < 0) {
                res = mid;
                lb = mid + 1;
            }
            else ub = mid - 1;
        }
        bool flag1 = false, flag2 = false;
        if ((LL)k * x + node[res].val >= 0) flag1 = true;
        if ((LL)-k * x + node[res + 1].val < 0) flag2 = true;
        if (res == N - 1) {
            if ((LL)k * x + node[res].val >= 0) {
                LL temp1 = ((-node[res].val - 1) / x + 1);
                k -= temp1;
                node[res].val += temp1 * x;
            }
            else flag = -1;
        }
        else if (flag1 && flag2) {
            LL temp1 = ((-node[res].val - 1) / x + 1);
            LL temp2 = (node[res + 1].val / x + 1);
            // cout<<temp1<<" "<<temp2<<endl;
            if (temp1 == temp2) {
                if (abs(node[res].val) > abs(node[res + 1].val)) {
                    k -= temp2;
                    node[res + 1].val -= temp2 * x;
                }
                else {
                    k -= temp1;
                    node[res].val += temp1 * x;
                }
            }
            else if (temp1 > temp2) {
                k -= temp2;
                node[res + 1].val -= temp2 * x;
            }
            else {
                k -= temp1;
                node[res].val += temp1 * x;
            }
        }
        else if (flag1) {
            int temp1 = ((-node[res].val - 1) / x + 1);
            k -= temp1;
            node[res].val += temp1 * x;
        }
        else if (flag2) {
            int temp2 = (node[res + 1].val / x + 1);
            k -= temp2;
            node[res + 1].val -= temp2 * x;
        }
        else flag = -1;
    }
    else if (neg == 0) {
        if ((LL)-x * k + node[0].val < 0) {
            LL temp = (node[0].val / x + 1);
            k -= temp;
            node[0].val -= temp * x;
        }
        else flag = -1;
    }
    for (int i = 0; i < N; i ++) q.push((kk){node[i].pos, node[i].val});
    while (k > 0) {
        kk temp = q.top(); q.pop();
        if (temp.val < 0) temp.val -= flag * x;
        else temp.val += flag * x;
        k --;
        q.push((kk){temp.pos, temp.val});
    }
    int p = 0;
    while (!q.empty()) {
        kk temp = q.top(); q.pop();
        node[p ++] = (Node){temp.pos, temp.val};
    }
    sort(node, node + N, cmp2);
    for (int i = 0; i < N; i ++) cout<<node[i].val<<" ";
    return 0;
}
// LL a[MAX];

// struct Edge{
//     LL a,b;
//     int id;
//     bool operator < (const Edge &e)const{
//         return a>e.a;
//     }
// };

// LL labs(LL a){
//     if(a<0) return -a;
//     return a;
// }
// int main(){
//     //freopen("in.txt","r",stdin);
//     int n,k,x;
//     while(cin>>n>>k>>x){
//         int fu=0;
//         priority_queue<Edge> q;
//         for(int i=0;i<n;i++){
//             scanf("%I64d",&a[i]);
//             if(a[i]<0) fu++;
//             q.push((Edge){labs(a[i]),a[i],i});
//         }
//         while(k--){
//             Edge tmp=q.top();q.pop();
//             if(fu%2){
//                 tmp.a+=x;
//                 if(tmp.b<0) tmp.b-=x;
//                 else tmp.b+=x;
//                 a[tmp.id]=tmp.b;
//             }
//             else{
//                 if(tmp.b<0){
//                     tmp.b+=x;
//                     if(tmp.b>=0) fu--;
//                 }
//                 else{
//                     tmp.b-=x;
//                     if(tmp.b<0) fu++;
//                 }
//                 tmp.a=labs(tmp.b);
//                 a[tmp.id]=tmp.b;
//             }
//             q.push(tmp);
//         }
//         for(int i=0;i<n;i++){
//             printf("%I64d ",a[i]);
//         }
//         cout<<endl;
//     }
//     return 0;
// }