c/c++语言开发共享cf1130E. Wrong Answer(构造)

题意

题目链接

sol

对构造一无所知。。。

题解的方法比较神仙，，设第一个位置为(-1)，(s = sum_{i=1}^n a_i)

那么我们要让(n * s – (n – 1) * (s + 1) = k)

固定(n)之后可以直接解出(s)。。。

#include<bits/stdc++.h>  #define pair pair<ll, ll> #define mp(x, y) make_pair(x, y) #define fi first #define se second #define ll long long  #define fin(x) {freopen(#x".in","r",stdin);} #define fout(x) {freopen(#x".out","w",stdout);} using namespace std; const int maxn = 2001, mod =666623333, inf = 1e9 + 10; const double eps = 1e-9; template <typename a, typename b> inline bool chmin(a &a, b b){if(a > b) {a = b; return 1;} return 0;} template <typename a, typename b> inline bool chmax(a &a, b b){if(a < b) {a = b; return 1;} return 0;} template <typename a, typename b> inline ll add(a x, b y) {if(x + y < 0) return x + y + mod; return x + y >= mod ? x + y - mod : x + y;} template <typename a, typename b> inline void add2(a &x, b y) {if(x + y < 0) x = x + y + mod; else x = (x + y >= mod ? x + y - mod : x + y);} template <typename a, typename b> inline ll mul(a x, b y) {return 1ll * x * y % mod;} template <typename a, typename b> inline void mul2(a &x, b y) {x = (1ll * x * y % mod + mod) % mod;} template <typename a> inline void debug(a a){cout << a << 'n';} template <typename a> inline ll sqr(a x){return 1ll * x * x;} 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', c = getchar();     return x * f; } int n = 2000, a[maxn]; signed main() {     a[1] = -1;     int lim = 1e6, k = read(), s = k + n;     for(int i = 2; i <= n; i++)          if(s > lim) a[i] = lim, s -= lim;         else {a[i] = s; break;}     cout << n << 'n';     for(int i = 1; i <= n; i++) cout << a[i] << " ";     return 0; }