# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
95946 | Retro3014 | Skyscraper (JOI16_skyscraper) | C++17 | 4 ms | 376 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <iostream>
#include <stdio.h>
#include <vector>
#include <algorithm>
#include <deque>
using namespace std;
typedef long long ll;
#define MAX_N 100
#define DIV 1000000007LL
int N;
vector<int> v;
ll ans;
bool chk[MAX_N+1];
int arr[MAX_N+1];
ll L, L2;
int zero(int x){
return (x>0?x:-x);
}
int cost(int x, int y){
if(x==-1 || y==-1) return 0;
return zero(v[x]-v[y]);
}
void dfs(int x){
if(x==N){
if(L>=L2){
ans++;
return;
}
}else{
for(int i=0; i<N; i++){
if(!chk[i]){
arr[x] = i;
chk[i] = true;
if(x!=0){
L2+=(ll)zero(v[arr[x]]-v[arr[x-1]]);
}
dfs(x+1);
chk[i] = false;
if(x!=0){
L2-=(ll)zero(v[arr[x]]-v[arr[x-1]]);
}
arr[x] = 0;
}
}
}}
void solve1(){
dfs(0);
return;}
#define MAX_K 20000
#define MAX_N2 14
#define MAX_L 100
ll dp[MAX_K+1][MAX_N2+1][MAX_L+1];
bool in[MAX_K+1][MAX_N2+1][MAX_L+1];
struct S{
S (int x, int y, int z) : x(x), y(y), z(z) {}
int x, y, z;
};
deque<S> dq;
void solve2(){
dp[0][0][0] = 1;
in[0][0][0] = true;
dq.push_back({0, -1, 0});
while(!dq.empty()){
S now = dq.front(); dq.pop_front();
int two = 1;
for(int i=0; i<N; i++){
if((two&now.x==0)){
if(now.z+cost(i, now.y)<=L){
S add(now.x+two, i, now.z+cost(i, now.y));
dp[add.x][add.y][add.z]+=dp[now.x][now.y][now.z];
dp[add.x][add.y][add.z]=dp[add.x][add.y][add.z]%DIV;
if(!in[add.x][add.y][add.z]){
dq.push_back(add); in[add.x][add.y][add.z] = true;
}
}
}
two*=2;
}
}
int idx = (1<<N)-1;
for(int i=0; i<N; i++){
for(int j=0; j<=L; j++){
ans+=dp[idx][i][j];
ans=ans%DIV;
}
}
return;
}
int main(){
scanf("%d%lld", &N, &L);
for(int i=0; i<N; i++){
int x; scanf("%d", &x); v.push_back(x);
}
if(N<=8){
solve1();
}else{
solve2();
}
printf("%lld", ans);
return 0;
}
Compilation message (stderr)
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