MINROAD - VOI 2014 - Con đường Tùng Trúc
Tác giả: RR
Ngôn ngữ: C++
#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define DEBUG(x) { cout << #x << " = "; cout << x << endl; }
#define PR(a,n) { cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl; }
#define PR0(a,n) { cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl; }
using namespace std;
//Buffer reading
int INP,AM,REACHEOF;
const int BUFSIZE = (1<<12) + 17;
char BUF[BUFSIZE+1], *inp=BUF;
#define GETCHAR(INP) { \
if(!*inp && !REACHEOF) { \
memset(BUF,0,sizeof BUF);\
int inpzzz = fread(BUF,1,BUFSIZE,stdin);\
if (inpzzz != BUFSIZE) REACHEOF = true;\
inp=BUF; \
} \
INP=*inp++; \
}
#define DIG(a) (((a)>='0')&&((a)<='9'))
#define GN(j) { \
AM=0;\
GETCHAR(INP); while(!DIG(INP) && INP!='-') GETCHAR(INP);\
if (INP=='-') {AM=1;GETCHAR(INP);} \
j=INP-'0'; GETCHAR(INP); \
while(DIG(INP)){j=10*j+(INP-'0');GETCHAR(INP);} \
if (AM) j=-j;\
}
//End of buffer reading
const int MN = 300111;
const int oo = 1000111000;
int n, a, b, c1[MN], c2[MN];
pair<int,int> x[MN];
int main() {
ios :: sync_with_stdio(false);
cin >> n >> a >> b;
FOR(i,1,n) cin >> x[i].first >> x[i].second;
sort(x+1, x+n+1);
FOR(i,1,n) {
c1[i] = c1[i-1] + (x[i].second == 1);
c2[i] = c2[i-1] + (x[i].second == 2);
}
int best = oo;
FOR(i,1,n) {
if (c1[i] < a || c2[i] < b) continue;
int left = 1, right = i, res = 1;
while (left <= right) {
int mid = (left + right) >> 1;
if (c1[i] - c1[mid-1] >= a && c2[i] - c2[mid-1] >= b) {
res = mid;
left = mid + 1;
}
else right = mid - 1;
}
best = min(best, x[i].first - x[res].first);
}
if (best == oo) cout << -1; else cout << best;
cout << endl;
return 0;
}