Submission #587520

#TimeUsernameProblemLanguageResultExecution timeMemory
587520benson1029Sorting (IOI15_sorting)C++14
0 / 100
3 ms468 KiB
#include "sorting.h" #include<bits/stdc++.h> using namespace std; int a[200005], b[200005], s[200005]; bool stexists[200005]; vector< pair<int,int> > v; queue<int> st; void swapa(int x, int y) { b[a[x]] = y; b[a[y]] = x; if(!stexists[x] && stexists[y]) { st.push(x); } else if(stexists[x] && !stexists[y]) { st.push(y); } swap(stexists[x], stexists[y]); swap(a[x], a[y]); } int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) { int l = 0, r = N, mid; while(l <= r) { mid = (l+r)/2; for(int i=0; i<N; i++) { a[i] = i; s[i] = S[i]; } for(int i=mid-1; i>=0; i--) { swap(a[X[i]], a[Y[i]]); } while(!st.empty()) st.pop(); for(int i=0; i<N; i++) { stexists[i] = (a[i] != s[i]); if(a[i] != s[i]) st.push(i); b[a[i]] = i; } v.clear(); for(int i=0; i<mid; i++) { swapa(X[i], Y[i]); swap(s[X[i]], s[Y[i]]); int j = 200001; while(!st.empty() && !stexists[j]) { j = st.front(); st.pop(); } if(!stexists[j]) { v.push_back({0, 0}); continue; } int k = b[s[j]]; swap(s[j], s[k]); v.push_back({j, k}); if(s[j] == a[j]) { stexists[j] = false; } if(s[k] == a[k]) { stexists[k] = false; } } if(l==r) { for(int i=0; i<v.size(); i++) P[i] = v[i].first, Q[i] = v[i].second; return v.size(); } else { while(!st.empty() && !stexists[st.front()]) st.pop(); if(st.empty()) r = mid; else l = mid+1; } } }

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:68:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |    for(int i=0; i<v.size(); i++) P[i] = v[i].first, Q[i] = v[i].second;
      |                 ~^~~~~~~~~
sorting.cpp:69:17: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   69 |    return v.size();
      |           ~~~~~~^~
sorting.cpp:24:39: warning: unused parameter 'M' [-Wunused-parameter]
   24 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
      |                                   ~~~~^
sorting.cpp:76:1: warning: control reaches end of non-void function [-Wreturn-type]
   76 | }
      | ^
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