Submission #66168423

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int MX=111;
int n,a[MX],b[MX],sa[MX],sb[MX];
vector<pii> ans;
bool was;
void local_swap(int i, int j) {
  ans.emplace_back(i,j);
  swap(a[i],a[j]);
  --a[i];
  ++a[j];
}
pii perform_swap(int i, int j) {
  if (i==1 && j==n) {
    perform_swap(1,2);
    i=2;
  }
  if (i>1) {
    local_swap(1,i);
    local_swap(1,j);
    local_swap(1,i);
  } else {
    local_swap(i,n);
    local_swap(j,n);
    local_swap(i,n);
  }
  return {i,j};
}
int main() {
  scanf("%d",&n);
  for (int i=1; i<=n; i++) { scanf("%d",&a[i]); sa[i-1]=a[i]; }
  for (int i=1; i<=n; i++) { scanf("%d",&b[i]); sb[i-1]=b[i]; if (b[i]!=a[i]) was=true; }
  if (!was) {
    puts("Yes");
    puts("0");
    return 0;
  }
  if (n==2) {
    if (a[1]==b[2]-1 && a[2]==b[1]+1) {
      puts("Yes");
      puts("1");
      puts("1 2");
    } else puts("No");
    return 0;
  }
  sort(sa,sa+n);
  sort(sb,sb+n);
  while (true) {
    int wl=-1,wr=-1,idxl,idxr;
    for (int i=0; i<n; i++) if (sa[i]<sb[i]) { wl=i; break; }
    for (int i=0; i<n; i++) if (sa[i]>sb[i]) { wr=i; break; }
    if (wl==-1 && wr==-1) break;
    if (wl==-1 || wr==-1) { puts("No"); return 0; }
    for (int i=1; i<=n; i++) if (sa[wl]==a[i]) { idxl=i; break; }
    for (int i=1; i<=n; i++) if (i!=idxl && sa[wr]==a[i]) { idxr=i; break; }
    pair<int,int> p{idxl,idxr};
    if (idxl>idxr) p=perform_swap(idxr,idxl);
    local_swap(p.first,p.second);
    --sa[wr];
    ++sa[wl];
    sort(sa,sa+n);
  }
  for (int i=1; i<=n; i++) if (a[i]!=b[i]) {
    was=false;
    for (int j=i+1; j<=n; j++) if (a[j]==b[i]) {
      perform_swap(i,j);
      was=true;
      break;
    }
    if (!was) { puts("No"); return 0; }
  }
  puts("Yes");
  printf("%d\n",int(ans.size()));
  for (int i=0; i<ans.size(); i++) printf("%d %d\n",ans[i].first,ans[i].second);
  return 0;
}

Submission Info

Compile Error

Main.cpp: In function ‘int main()’:
Main.cpp:75:18: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<std::pair<int, int> >::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   75 |   for (int i=0; i<ans.size(); i++) printf("%d %d\n",ans[i].first,ans[i].second);
      |                 ~^~~~~~~~~~~
Main.cpp:31:8: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   31 |   scanf("%d",&n);
      |   ~~~~~^~~~~~~~~
Main.cpp:32:35: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   32 |   for (int i=1; i<=n; i++) { scanf("%d",&a[i]); sa[i-1]=a[i]; }
      |                              ~~~~~^~~~~~~~~~~~
Main.cpp:33:35: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   33 |   for (int i=1; i<=n; i++) { scanf("%d",&b[i]); sb[i-1]=b[i]; if (b[i]!=a[i]) was=true; }
      |                              ~~~~~^~~~~~~~~~~~
Main.cpp:58:34: warning: ‘idxr’ may be used uninitialized [-Wmaybe-uninitialized]
   58 |     if (idxl>idxr) p=perform_swap(idxr,idxl);
      |                      ~~~~~~~~~~~~^~~~~~~~~~~
Main.cpp:50:26: note: ‘idxr’ was declared here
   50 |     int wl=-1,wr=-1,idxl,idxr;
      |                          ^~~~
Main.cpp:56:30: warning: ‘idxl’ may be used uninitialized [-Wmaybe-uninitialized]
   56 |     for (int i=1; i<=n; i++) if (i!=idxl && sa[wr]==a[i]) { idxr=i; break; }
      |                              ^~
Main.cpp:50:21: note: ‘idxl’ was declared here
   50 |     int wl=-1,wr=-1,idxl,idxr;
      |                     ^~~~

Judge Result