HDU 4883 tiankeng's Restaurant

Question link: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 4883

Solution Report: There are n waves of guests in a restaurant each day. The arrival time of the I wave k guest is S, and the departure time is E. How many people can find the most popular restaurants?

At first, I wrote it using a line segment tree, but re. Later I saw a method that was very clever: all the time in a day was converted into minutes, ranging from 0 to 1440, all are initialized to 0, and if there are K

When the guests arrive, they will be in the s position + K of the array, and then-K at the departure time. Finally, they will scan the array and judge the maximum value during the scanning process.

 1 #include<cstdio> 2 #include<cstring> 3 #include<iostream> 4 #include<algorithm> 5 using namespace std; 6 const int maxn = 1500; 7 int que[maxn],T,n; 8  9 int main()10 {11     scanf("%d",&T);12     while(T--)13     {14         scanf("%d",&n);15         memset(que,0,sizeof(que));16         int d,s1,s2,e1,e2;17         while(n--)18         {19             scanf("%d %d:%d %d:%d",&d,&s1,&s2,&e1,&e2);20             s1 = 60 * s1 + s2;21             e1 = 60 * e1 + e2;22             que[s1] += d;23             que[e1] -= d;24         }25         int tot = 0,ans = 0;26         for(int i = 0;i <= 1440;++i)27         {28             tot += que[i];29             ans = max(ans,tot);30         }31         printf("%d\n",ans);32     }33     return 0;34 }

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