2012-06-02 10:47:28Morris
[UVA] 10036 - Divisibility
Problem C: Divisibility
Consider an arbitrary sequence of integers. One can place + or - operators between integers in the sequence, thus deriving different arithmetical expressions that evaluate to different values. Let us, for example, take the sequence: 17, 5, -21, 15. There are eight possible expressions:
| 17 | + | 5 | + | -21 | + | 15 | = | 16 |
| 17 | + | 5 | + | -21 | - | 15 | = | -14 |
| 17 | + | 5 | - | -21 | + | 15 | = | 58 |
| 17 | + | 5 | - | -21 | - | 15 | = | 28 |
| 17 | - | 5 | + | -21 | + | 15 | = | 6 |
| 17 | - | 5 | + | -21 | - | 15 | = | -24 |
| 17 | - | 5 | - | -21 | + | 15 | = | 48 |
| 17 | - | 5 | - | -21 | - | 15 | = | 18 |
You are to write a program that will determine divisibility of sequence of integers.
Input
The first line of the input file contains a integer M indicating the number of cases to be analyzed. Then M couples of lines follow.For each one of this couples, the first line contains two integers, N and K (1 <= N <= 10000, 2 <= K <= 100) separated by a space. The second line contains a sequence of N integers separated by spaces. Each integer is not greater than 10000 by it's absolute value.
Output
For each case in the input file, write to the output file the word "Divisible" if given sequence of integers is divisible by K or "Not divisible" if it's not.Sample input
2 4 7 17 5 -21 15 4 5 17 5 -21 15
Sample Output
Divisible Not divisible
第一次用 set 就跑很慢, 結果最後還是用老方法
//ANSI C 0.032 s
#include <stdio.h>
#include <string.h>
int main() {
int t, n, m, x, y, i, j;
scanf("%d", &t);
char ch[2][100];
while(t--) {
scanf("%d %d", &n, &m);
memset(ch, 0, sizeof(ch));
scanf("%d", &x);
x = x%m;
if(x < 0) x += m;
ch[0][x] = 1;
char flag;
for(i = 1, flag = 0; i < n; i++, flag ^= 1) {
scanf("%d", &x);
x = x%m;
if(x < 0) x += m;
for(j = 0; j < m; j++) {
if(ch[flag][j]) {
y = j+x;
if(y >= m) y -= m;
ch[flag^1][y] = 1;
y = j-x;
if(y < 0) y += m;
ch[flag^1][y] = 1;
}
}
memset(ch[flag], 0, sizeof(ch[flag]));
}
int ans = ch[flag][0];
puts(ans ? "Divisible" : "Not divisible");
}
return 0;
}