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

来源：互联网发布：预测算法有哪些编辑：程序博客网时间：2024/05/17 23:13
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            secondconst 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;// }
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