CodeForces 731B Coupons and Discounts

模拟。

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<ctime>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-10;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
template <class T>
inline void read(T &x)
{
    char c = getchar();
    x = 0;
    while(!isdigit(c)) c = getchar();
    while(isdigit(c))
    {
        x = x * 10 + c - ‘0‘;
        c = getchar();
    }
}

int a[200010],n;

int main()
{
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    bool fail=0;
    for(int i=1;i<n;i++)
    {
        if(a[i]<0) fail=1;
        a[i]=a[i]%2;
        if(a[i]==1)
        {
            a[i]--;
            a[i+1]--;
        }
    }
    a[n]=a[n]%2;
    if(a[n]!=0) fail=1;

    if(fail==1) printf("NO\n");
    else printf("YES\n");

    return 0;
}
时间: 2024-09-28 16:14:09

CodeForces 731B Coupons and Discounts的相关文章

CodeForces 731B Coupons and Discounts (水题模拟)

题意:有n个队参加CCPC,然后有两种优惠方式,一种是一天买再次,一种是买两天,现在让你判断能不能找到一种方式,使得优惠不剩余. 析:直接模拟,如果本次是奇数,那么就得用第二种,作一个标记,再去计算下一个. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #inclu

CodeForces 754D Fedor and coupons ——(k段线段最大交集)

还记得lyf说过k=2的方法,但是推广到k是其他的话有点麻烦.现在这里采取另外一种方法. 先将所有线段按照L进行排序,然后优先队列保存R的值,然后每次用最小的R值,和当前的L来维护答案即可.同时,如果Q的size()比k大,那么就弹出最小的R. 具体见代码: 1 #include <stdio.h> 2 #include <algorithm> 3 #include <string.h> 4 #include <set> 5 #include <vec

CodeForces 754D Fedor and coupons (优先队列)

题意:给定n个优惠券,每张都有一定的优惠区间,然后要选k张,保证k张共同的优惠区间最大. 析:先把所有的优惠券按左端点排序,然后维护一个容量为k的优先队列,每次更新优先队列中的最小值,和当前的右端点, 之间的距离.优先队列只要存储右端点就好. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <

【codeforces 718E】E. Matvey&#39;s Birthday

题目大意&链接: http://codeforces.com/problemset/problem/718/E 给一个长为n(n<=100 000)的只包含‘a’~‘h’8个字符的字符串s.两个位置i,j(i!=j)存在一条边,当且仅当|i-j|==1或s[i]==s[j].求这个无向图的直径,以及直径数量. 题解:  命题1:任意位置之间距离不会大于15. 证明:对于任意两个位置i,j之间,其所经过每种字符不会超过2个(因为相同字符会连边),所以i,j经过节点至多为16,也就意味着边数至多

Codeforces 124A - The number of positions

题目链接:http://codeforces.com/problemset/problem/124/A Petr stands in line of n people, but he doesn't know exactly which position he occupies. He can say that there are no less than a people standing in front of him and no more than b people standing b

Codeforces 841D Leha and another game about graph - 差分

Leha plays a computer game, where is on each level is given a connected graph with n vertices and m edges. Graph can contain multiple edges, but can not contain self loops. Each vertex has an integer di, which can be equal to 0, 1 or  - 1. To pass th

Codeforces Round #286 (Div. 1) A. Mr. Kitayuta, the Treasure Hunter DP

链接: http://codeforces.com/problemset/problem/506/A 题意: 给出30000个岛,有n个宝石分布在上面,第一步到d位置,每次走的距离与上一步的差距不大于1,问走完一路最多捡到多少块宝石. 题解: 容易想到DP,dp[i][j]表示到达 i 处,现在步长为 j 时最多收集到的财富,转移也不难,cnt[i]表示 i 处的财富. dp[i+step-1] = max(dp[i+step-1],dp[i][j]+cnt[i+step+1]) dp[i+st

Codeforces 772A Voltage Keepsake - 二分答案

You have n devices that you want to use simultaneously. The i-th device uses ai units of power per second. This usage is continuous. That is, in λ seconds, the device will use λ·ai units of power. The i-th device currently has bi units of power store

Educational Codeforces Round 21 G. Anthem of Berland(dp+kmp)

题目链接:Educational Codeforces Round 21 G. Anthem of Berland 题意: 给你两个字符串,第一个字符串包含问号,问号可以变成任意字符串. 问你第一个字符串最多包含多少个第二个字符串. 题解: 考虑dp[i][j],表示当前考虑到第一个串的第i位,已经匹配到第二个字符串的第j位. 这样的话复杂度为26*n*m*O(fail). fail可以用kmp进行预处理,将26个字母全部处理出来,这样复杂度就变成了26*n*m. 状态转移看代码(就是一个kmp