书的复制

 第四题。

原题链接：https://www.luogu.org/problem/show?pid=1281#sub

借鉴了一篇题解的思路。

 1 #include <cstring>
 2 #include <cstdio>
 3 #include <iostream>
 4 #include <cmath>
 5 #include <algorithm>
 6 #define maxn 1005
 7 using namespace std;
 8 int n,m,book[maxn];
 9 int ans;
10 inline int read(){
11     int num = 0;
12     char c;
13     bool flag = false;
14     while ((c = getchar()) == ' ' || c == '\n' || c == '\r');
15     if (c == '-')
16         flag = true;
17     else
18         num = c - '0';
19     while (isdigit(c = getchar()))
20         num = num * 10 + c - '0';
21     return (flag ? -1 : 1) * num;
22 }
23 bool check(int now){
24     int ans=1;
25     int tot=0;
26     for(int i=n;i>=1;i--){
27         if(tot + book[i] > now){
28             tot = book[i];
29             ans++;
30         }
31         else
32             tot += book[i];
33     }
34     if (ans > m) 
35         return false;
36     else
37         return true;
38 }
39 int main(){
40     n = read();m = read();
41     int l=0;int r =0;
42     for(int i=1;i<=n;i++){
43         book[i] = read();
44         r += book[i];
45     }
46     while(l < r){
47         int mid=(l+r) >> 1;
48         if(check(mid)) 
49             r=mid;
50         else 
51             l=mid+1;
52     }
53     ans = l;
54     int out[maxn][2];
55     int cnt = n;
56     int now = ans;
57     for(int i=m;i>=1;i--){
58         out[i][2] = cnt;
59         while(now - book[cnt] >= 0){
60             now -= book[cnt--];
61             if(cnt == 0) 
62                 break;
63         }
64         out[i][1] = cnt + 1;
65         now = ans;
66     }
67     for(int i=1;i<=m;i++)
68         printf("%d %d\n",out[i][1],out[i][2]);
69     return 0;
70 }

 

posted @ 2017-10-21 23:59  ShawnZhou_Aether  阅读(164)  评论(0)  编辑  收藏  举报