Morris' Blog 我在摸索我存在的意義、生命的意義、內涵及價值。 沒有真正神手般的厲害，套用模式是大部分的情況。 沒那麼厲害的我存在的意義為何，襯托出神的存在？ 有時候不能怪別人不給我機會，我已經開始省思， 為什麼我沒有給別人機會的原因，而是全要靠別人。 有時候我認為我與眾不同，那是因為我做不到很多人能辦到的事情。 我聽不到、玩不起來、說得不夠明瞭、理解得不夠多， 我缺少的語文能力，就是一切一切無能的判定。 為此，我不曉得能做些對別人有幫助的事情。 我知道我自己是個不服輸的性格，但現在我不得不認輸。 我沒有能力，因此我必須認輸。 我到底來這世界作什麼？處處充滿不確定性， 而我總是無法出類拔萃，想當個一般人似乎也回不了頭了。 越強大的挑戰需要越強力的支持，而我的支持是什麼？ 最近嘗試與人談話，但都是失敗的結局，沒人能接受， 不需要言語，不需要溝通，一切所想都表達不出來。

49愛的鼓勵 6訂閱站台

Problem K

Dog and Gopher

Input: standardinput

Output: standardoutput

Time Limit: 1 second

Memory Limit: 32 MB

A large field has a gopher and adog. The dog wants to eat the gopher, while the gopher wants to run to safetythrough one of several gopher holes dug in the surface of the field.

Neither the dog nor the gopher is a math major;however, neither is entirely stupid. The gopher decides on a particular gopherhole and heads for that hole in a straight line at a fixed speed. The dog, whichis very good at reading body language, anticipates which hole the gopher haschosen, and heads at double the speed of the gopher to the hole, where itintends to gobble up the gopher. If the dog reaches the hole first, the gophergets gobbled; otherwise, the gopher escapes.

You have to select a hole for the gopher throughwhich it can escape, if such a hole exists.

Input

The input file contains several sets of input.The first line of each set contains one integer and four floating pointnumbers. The integer n denotes howmany holes are in the set and the four floating point numbers denote the (x,y) coordinates of the gopherfollowed by the (x,y) coordinates ofthe dog. Subsequent n lines of inputeach contain two floating point numbers: the (x, y) coordinates of a gopher hole. All distances are in meters;to the nearest mm. Input isterminated by end of file. There is a blank line between two consecutive sets.

Output

Your shouldoutput a single line for each set of input. For each set, if the gopher canescape the output line should read "Thegopher can escape through the hole at (x,y)." identifying the appropriatehole to the nearest mm. Otherwise the output line should read "The gopher cannot escape."If the gopher may escape through more than one hole, report the one thatappears first in the input. There are not more than 1000 gopher holes in a set of input and all coordinates are between-10000 and +10000.

Sample Input:

1 1.000 1.000 2.000 2.000

1.500 1.500

2 2.000 2.000 1.000 1.000

1.500 1.500

2.500 2.500

Sample Output

The gopher cannot escape.

The gopher can escape through the hole at (2.500,2.500).

(Joint Effort Contest, Source: Waterloo ACM Programming Contest)

 #include <stdio.h>

int main() {
    int n;
    double x1,y1, x2, y2;
    while(scanf("%d %lf %lf %lf %lf", &n, &x1, &y1, &x2, &y2) == 5) {
        int find = 0;
        double x, y, ansx, ansy;
        while(n--) {
            scanf("%lf %lf", &x, &y);
            if(find)
                continue;
            if(4*((x1-x)*(x1-x)+(y1-y)*(y1-y)) <= (x2-x)*(x2-x)+(y2-y)*(y2-y)) {
                find = 1;
                ansx = x;
                ansy = y;
            }
        }
        if(find) {
            printf("The gopher can escape through the hole at (%.3lf,%.3lf).\n", ansx, ansy);
        } else {
            puts("The gopher cannot escape.");
        }
    }
    return 0;
}