oj.uz

Submission #240068

# Submission time Handle Problem Language Result Execution time Memory
240068 2020-06-17T21:26:43 Z m3r8 Building Bridges (CEOI17_building) C++14
100 / 100
 144 ms 9656 KB 
#include <stdio.h>
#include <set>
#include <algorithm>

#define ll long long
#define INF 1e9
#define MINF -INF
#define N 100100

int flag;
ll w[N];
ll h[N];

struct line{
  ll m;
  ll b;
  double start;
  double end;
};
struct compare{
  bool operator()(line a, line b){
    if(!flag){
      if(a.m != b.m){
        return a.m > b.m;
      }else{
        if(a.b != b.b){
          return a.b > b.b;
        }else{
          return a.start < b.start;  
        };
      };
    }else{
      return a.start < b.start;  
    };
  };
};
double is(line a, line b){
  return ((double)(a.b - b.b))/((double)(b.m-a.m));  
};

std::set<line,compare> hull;

void insert(ll m, ll b, int i){
  flag = 0;
  //printf("%lld %lld\n",m,b);
  line tmp = {m,b,INF,0.0};  
  line perf = {m,b,INF,0.0};
  line perfp;
  line perfn;
  double f1,f2;
  int ttm=0;

  auto it = (hull.insert(tmp)).first;
  auto itn = it;
  auto itp = it;
  auto itpp =it;
  ++itn;
  if(itn != hull.end() && itn->m == tmp.m){
    hull.erase(tmp);  
    return;
  };
  if(itn != hull.end() && itp != hull.begin()){
    double f1 = is(tmp,*itn);
    if(f1 <= itn->start){
      hull.erase(tmp);  
      return;
    };
  };
  if(itp != hull.begin()){
    itp--;
    while(itp != hull.begin()){
      itpp = itp;
      itp--;
      if(itpp->m == tmp.m){
        continue;  
      };
      f1 = is(tmp,*itpp);
      f2 = is(tmp,*itp);
      if(f1 > f2){
        ttm = 1;
        break;  
      };
    };
    if(ttm){
      itpp++;  
      itp++;
    };
    hull.erase(itpp,it);
    perf.start = is(tmp,*itp); 
    perfp = *itp;
    perfp.end = perf.start;
    hull.erase(itp);
    hull.insert(perfp);
  }else{
    perf.start = MINF;  
  };

  if(itn != hull.end()){
    itpp = itn;  
    itn++;
    while(itn != hull.end()){
      double f1 = is(*itn,*itpp);
      double f2 = is(tmp,*itn);
      if(f1 > f2)break;
      itpp = itn;
      itn++;
    };
    itn = it;
    itn++;
    hull.erase(itn,itpp);
    perf.end= is(tmp,*itpp);
    perfn = *itpp;
    perfn.start = perf.end;
    hull.erase(itpp);
    hull.insert(perfn);
  }else{
    perf.end = INF;
  };
  hull.erase(tmp);
  hull.insert(perf);
};

ll qry(ll x,int i){
  flag = 1;  
  line tmp = {0,0,(double)x,0};
  auto it = hull.lower_bound(tmp);
  it--;
  flag = 0;
  if(it->start <= x && it->end >= x){
    return it->m * x + it->b;  
  };
  //printf("Error\n");
  return -1;
};

//ll dp[N];

int main(void){
  int n;
  scanf("%d",&n);
  for(int i = 0;i<n;i++){
    scanf("%lld",&h[i]);
  };
  for(int i = 0;i<n;i++){
    scanf("%lld",&w[i]);  
    if(i != 0){
      w[i] += w[i-1];  
    };
  };
  ll tmp = 0;
  insert(-2 * h[0],0 - w[0] + h[0] * h[0],0);
  //dp[0] = 0;
  for(int i = 1;i<n;i++){
    /*for(auto j: hull){
      printf("%d %lld %lld %f %f\n",i,j.m,j.b,j.start,j.end);  
    };
    */
    tmp = qry(h[i],i) + w[i-1] + h[i] * h[i];  
    /*
    dp[i] = INF;
    for(int j = 0;j<i;j++){
      dp[i] = std::min(dp[i],dp[j] + (h[i]-h[j]) * (h[i]-h[j]) + w[i-1] - w[j]);  
    };
    if(dp[i] != tmp){
      for(auto j: hull){
        printf("%d %lld %lld %f %f\n",i,j.m,j.b,j.start,j.end);  
      };
      printf("tmp: %lld %lld %d %lld %lld\n",tmp,dp[i],i,h[i],qry(h[i],i));
      break;
    };
    */
    insert(-2 * h[i],tmp - w[i] + h[i] * h[i],i);
  };
  //printf("%lld\n",dp[n-1]);
  printf("%lld\n",tmp);
  return 0;  
};

Compilation message

building.cpp: In function 'int main()':
building.cpp:140:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&n);
   ~~~~~^~~~~~~~~
building.cpp:142:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&h[i]);
     ~~~~~^~~~~~~~~~~~~~
building.cpp:145:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld",&w[i]);  
     ~~~~~^~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 4 ms 256 KB Output is correct
3 Correct 4 ms 256 KB Output is correct
4 Correct 6 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 127 ms 1912 KB Output is correct
2 Correct 128 ms 1968 KB Output is correct
3 Correct 134 ms 1912 KB Output is correct
4 Correct 122 ms 1912 KB Output is correct
5 Correct 111 ms 3448 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 4 ms 256 KB Output is correct
3 Correct 4 ms 256 KB Output is correct
4 Correct 6 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 127 ms 1912 KB Output is correct
7 Correct 128 ms 1968 KB Output is correct
8 Correct 134 ms 1912 KB Output is correct
9 Correct 122 ms 1912 KB Output is correct
10 Correct 111 ms 3448 KB Output is correct
11 Correct 118 ms 1912 KB Output is correct
12 Correct 134 ms 1912 KB Output is correct
13 Correct 84 ms 1912 KB Output is correct
14 Correct 128 ms 2040 KB Output is correct
15 Correct 144 ms 9656 KB Output is correct
16 Correct 113 ms 3448 KB Output is correct
17 Correct 38 ms 1792 KB Output is correct
18 Correct 38 ms 1912 KB Output is correct