第七届题目
煤球数目
#include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { long long cnt=0,sum=0; for(int i=1;i<=100;i++) { cnt+=i; sum+=cnt; } printf("%lld",sum); return 0; }生日蜡烛
#include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { printf("26"); return 0; }凑算式（暴力）
#include <stdio.h> int main() { int sum = 0; for (int i = 1; i < 10; i++) { for (int j = 1; j < 10; j++) { for (int k = 1; k < 10; k++) { for (int l = 1; l < 10; l++) { for (int m = 1; m < 10; m++) { for (int n = 1; n < 10; n++) { for (int o = 1; o < 10; o++) { for (int p = 1; p < 10; p++) { for (int q = 1; q < 10; q++) { if ((i + (double)j / k + (double)(l * 100 + 10 * m + n) / (100 * o + 10 * p + q) == 10) && i != j && i != k && i != l && i != m && i != n && i != o && i != p && i != q && j != k && j != l && j != m && j != n && j != o && j != p && j != q && k != l && k != m && k != n && k != o && k != p && k != q && l != m && l != n && l != o && l != p && l != q && m != n && m != o && m != p && m != q && n != o && n != p && n != q && o != p && o != q && p != q) { sum++; } } } } } } } } } } printf("%d\n", sum); return 0; }方格填数
不能相邻转化为相减不等于1
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> void swap(int *a, int *b) { int temp = *a; *a = *b; *b = temp; } void reverse(int nums[], int start, int end) { while (start < end) { swap(&nums[start], &nums[end]); start++; end--; } } bool next_permutation(int nums[], int n) { int i = n - 2; while (i >= 0 && nums[i] >= nums[i+1]) { i--; } if (i < 0) { return false; } int j = n - 1; while (nums[j] <= nums[i]) { j--; } swap(&nums[i], &nums[j]); reverse(nums, i+1, n-1); return true; } int main() { int nums[10] = {0,1,2,3,4,5,6,7,8,9}; int ans = 0; do { if ( abs(nums[0]-nums[1])!=1 && abs(nums[0]-nums[3])!=1 && abs(nums[0]-nums[4])!=1 && abs(nums[0]-nums[5])!=1&& abs(nums[1]-nums[2])!=1 && abs(nums[1]-nums[4])!=1 && abs(nums[1]-nums[5])!=1 && abs(nums[1]-nums[6])!=1 && abs(nums[2]-nums[5])!=1 && abs(nums[2]-nums[6])!=1 && abs(nums[3]-nums[4])!=1 && abs(nums[3]-nums[7])!=1 && abs(nums[3]-nums[8])!=1 && abs(nums[4]-nums[5])!=1 && abs(nums[4]-nums[7])!=1 && abs(nums[4]-nums[8])!=1 && abs(nums[4]-nums[9])!=1 && abs(nums[5]-nums[6])!=1 && abs(nums[5]-nums[8])!=1 && abs(nums[5]-nums[9])!=1 && abs(nums[6]-nums[9])!=1 && abs(nums[7]-nums[8])!=1 && abs(nums[8]-nums[9])!=1 ) { ans++; } } while (next_permutation(nums, 10)); printf("%d\n", ans); return 0; }四平方和（暴力）
#include <stdio.h> #include <stdlib.h> #include <math.h> #define MAX 5000005 int main(int argc, char *argv[]) { int n; scanf("%d",&n); for(int a=0;a*a/4<=n;a++) { for(int b=a;b*b/3<=n;b++) { for(int c=b;c*c/2<=n;c++) { for(int d=c;d*d<=n;d++) { if((a*a+b*b+c*c+d*d)==n) { printf("%d %d %d %d",a,b,c,d); return 0; } } } } } return 0; }交换瓶子
注意swap函数 *和&的使用
#include <stdio.h> #include <stdlib.h> void swap(int *a,int *b) { int t=*a; *a=*b; *b=t; } int main(int argc, char *argv[]) { int n; scanf("%d",&n); int a[n]; for(int i=1;i<=n;i++) { scanf("%d",&a[i]); } int cnt=0; for(int i=1;i<=n;i++) { if(a[i]!=i) { cnt++; int idx=0; for(int j=i+1;j<=n;j++) { if(a[j]==i) { idx=j; break; } } swap(&a[i],&a[idx]); } } printf("%d",cnt); return 0; }最大比例
#include <stdio.h> #include <stdlib.h> typedef long long ll; const int N = 110; int compare(const void *a, const void *b) { ll num1 = *(const ll *)a; ll num2 = *(const ll *)b; if (num1 < num2) return -1; if (num1 > num2) return 1; return 0; } ll gcd(ll a, ll b) { if (b == 0) return a; else return gcd(b, a % b); } void swap_ll(ll *a, ll *b) { ll temp = *a; *a = *b; *b = temp; } ll gcd_sub(ll a, ll b) { if (a < b) swap_ll(&a, &b); if (b == 1) return a; return gcd_sub(b, a / b); } int main() { int n; ll x[N]; ll a[N], b[N]; int i; scanf("%d", &n); for (i = 0; i < n; i++) { scanf("%lld", &x[i]); } qsort(x, n, sizeof(ll), compare); ll c = 0; int cnt = 0; for (i = 1; i < n; i++) { if (x[i] != x[i-1]) { c = gcd(x[0], x[i]); a[cnt] = x[i] / c; b[cnt] = x[0] / c; cnt++; } } ll up = a[0], down = b[0]; for (i = 1; i < cnt; i++) { up = gcd_sub(up, a[i]); down = gcd_sub(down, b[i]); } printf("%lld/%lld\n", up, down); return 0; }