洛谷P2312 解方程(暴力)
阿新 • • 發佈:2018-10-23
bits mes i++ 解方程 pac its ace main vector
題意
題目鏈接
Sol
出這種題會被婊死的吧。。。
首先不難想到暴力判斷,然後發現連讀入都是個問題。
對於\(a[i]\)取模之後再判斷就行了。註意判斷可能會出現誤差,可以多找幾個模數
#include<bits/stdc++.h> #define Fin(x) {freopen(x, "r", stdin);} #define int long long using namespace std; const int MAXN = 2e5 + 10, mod = 19997; inline int read() { char c = getchar(); int x = 0, f = 1; while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();} while(c >= '0' && c <= '9') x = (x * 10 + c - '0') % mod, c = getchar(); return x * f; } int N, M, a[MAXN]; int add(int x, int y) { if(x + y < 0) return x + y + mod; else return x + y >= mod ? x + y - mod : x + y; } int mul(int x, int y) { return 1ll * x * y % mod; } int check(int val) { int now = 0; for(int i = N; i >= 0; i--) now = mul(now, val), now = add(now, a[i]); return now == 0; } signed main() { N = read(); M = read(); for(int i = 0; i <= N; i++) a[i] = read(); int ans = 0; vector<int> out; for(int i = 1; i <= M; i++) if(check(i)) ans++, out.push_back(i); printf("%d\n", ans); for(int i = 0; i < out.size(); i++) printf("%d\n", out[i]); return 0; }
洛谷P2312 解方程(暴力)