Acdream 1734 Can make a water problem? Greedy

Can you make a water problem?Time limit:2000/1000ms (java/others) Memory limit:128000/64000kb (java/others) Submit statistic Next Problemproblem Descriptionlosanto want to make a water problem. But he has no idea ....
Then he thought a problem:a bus arrived at a station, and there were X persons got off the bus, then y persons got on the Bus. And there were r persons (include the driver) on the bus before the bus in next station. How many is on the bus initially? The driver can ' t get on or off the bus. There is a 1 driver in the bus.
But if the x=8, y=5 r=4, there is something wrong in the problem. After got on 5 persons and there is 4 persons rest ... What a pity! Losanto give x, Y, R want know whether the problem is OK.
Of course few buses have only one station, so there is n stations.
Now give your x and Y for every station, and there are only one person (the driver) rest after the last station. Can you find a suitable order for the station and make the problem OK? Input

There is several cases.

For each case, the first line there is a n, indicate n stations. Then n lines followed, each of which has a numbers XI and Yi. The problem easier, we guarantee that xi>=yi. ( 0<n<100000 0<=xi,yi<1000000) Outputfor each cases, output one, and "Yes" (if you can make a OK order) or "No" (If you can ' t). Sample Input

25 07 425) 23 3

Sample Output

YesNo

MANAGERRIHKDDD Test Instructions: There are n stations, give each station the number of alighted Xi and the number of people Yi, ask how to order the station to meet the objective conditions. Analysis: The station according to the number of passengers from more than a few sorts, and then judged whether the objective conditions, that is, the number of cars should not be less than the number of passengers.

#include <cstdio>#include<iostream>#include<cstring>#include<cmath>#include<stdlib.h>#include<vector>#include<queue>#include<stack>#include<algorithm>#defineLL Long Longusing namespacestd;Const intmaxn=100000+5; LL tot;intN;structnode{intx, y; BOOL operator< (ConstNode A)Const    {        returnx-y>a.x-a.y; }}A[MAXN];BOOLCheak () { for(intI=0; i<n;i++)    {        if(tot<a[i].x)return false; Tot-=a[i].y; }    return true;}intMain () { while(SCANF ("%d", &n)! =EOF) {Tot=0;  for(intI=0; i<n;i++) {scanf ("%d%d",&a[i].x,&a[i].y); Tot+ = (a[i].x-a[i].y); A[i].y= (a[i].x-a[i].y); } sort (A,a+N); Puts (Cheak ()?"Yes":"No"); }    return 0;}

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Acdream 1734 Can make a water problem? Greedy