2 条题解
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#include <bits/stdc++.h> using namespace std; #define rep(i, l, r) for (int i = l; i <= r; i++) #define int long long #define endl '\n' void solve() { int n,d; cin >> n >> d; while(n--){ int x,ok = 0; // ok：是否合法的标记 cin >> x; if(x >= 10 * d){ cout << "YES" << '\n'; continue; } while(x > 0){ if(x % d == 0){ ok = 1; cout << "YES" << '\n'; break; } x -= 10; } if(!ok) cout << "NO" << '\n'; } } signed main() { ios::sync_with_stdio(0); cin.tie(0),cout.tie(0); int T = 1; cin >> T; while (T--) solve(); return 0; }-
morgen
@ 2025-10-19 15:39:08
本题主要考查
数学规律推导与贪心策略的应用。多找些数看看什么哪些数合法。 -
morgen
@ 2025-10-19 15:39:23
若d == 7 易知下面是合法的数字 X 7 17 27 37 47 57 67 70 71 72 73 74 75 76 77 78 79 87 97 ...... 我们再看看下面合法的数 80 = 7 + 73 81 = 7 + 74 82 = 7 + 75 83 = 7 + 76 84 = 7 + 77 85 = 7 + 78 ...... 123 = 47 + 76 124 = 47 + 77 125 = 47 + 78 ...... 1233 = 1157 + 76 1234 = 1157 + 77 1235 = 1157 + 78 ...... 细心的你已经发现一些规律了 故：(1)若 X >= 10 * d ，则一定可以 那么若 X < 10 * d 呢？ 我们通过举例观察发现： 7 17 27 37 ... 可以 14 24 34 54 ... 也可以 14 = 7 + 7 = 7 * 1 + 7 = 7 * 2 + 10 * 0 24 = 7 + 17 = 7 * 1 + 17 = 7 * 2 + 10 * 1 34 = 7 + 27 = 7 * 1 + 27 = 7 * 2 + 10 * 2 ...... 21 = 7 + 7 + 7 = 7 * 2 + 7 = 7 * 3 + 10 * 0 31 = 7 + 7 + 17 = 7 * 2 + 17 = 7 * 3 + 10 * 1 41 = 7 + 7 + 27 = 7 * 2 + 27 = 7 * 3 + 10 * 2 51 = 7 + 7 + 37 = 7 * 2 + 37 = 7 * 3 + 10 * 3 ...... 细心的你已经发现一些规律了 故：(2)若 X < 10 * d 且 X == d * k1 + 10 * k2 (k1,k2 >= 0) 则一定可以 则：(3)若都不能满足上述(1),(2),则该X不合法 -
morgen
@ 2025-10-19 15:43:10
当 (x < 10d)时，循环中每次执行 (x -= 10)，最多执行的次数是常数次：
- d 的范围是 (1 <= d <= 9)，因此 10d 最大为 90，即 x 最大不超过 89。
- 每次减 10，最多循环 8次。
- 故代码不会超时。
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0
#include <stdio.h> int main(){ int t; scanf("%d",&t); while(t--){ int q,d; scanf("%d%d",&q,&d); for(int i=0;i<q;i++){ int a; scanf("%d",&a); if(a>=d*10)printf("YES\n"); else if(((a-d)%10==0||(a-d)%10==d)&&(a-d)>=0)printf("YES\n"); else if(((a-d-d)%10==0||(a-d-d)%10==d)&&(a-d-d)>=0)printf("YES\n"); else if(((a-d-d-d)%10==0||(a-d-d-d)%10==d)&&(a-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d)%10==0||(a-d-d-d-d)%10==d)&&(a-d-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d-d)%10==0||(a-d-d-d-d-d)%10==d)&&(a-d-d-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d-d-d)%10==0||(a-d-d-d-d-d-d)%10==d)&&(a-d-d-d-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d-d-d-d)%10==0||(a-d-d-d-d-d-d-d)%10==d)&&(a-d-d-d-d-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d-d-d-d-d)%10==0||(a-d-d-d-d-d-d-d-d)%10==d)&&(a-d-d-d-d-d-d-d-d)>=0)printf("YES\n"); else if(((a-d-d-d-d-d-d-d-d-d)%10==0||(a-d-d-d-d-d-d-d-d-d)%10==d)&&(a-d-d-d-d-d-d-d-d-d)>=0)printf("YES\n"); else printf("NO\n"); } } }
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