【POJ】2823 Sliding Window

单调队列。

 /* 2823 */
 #include <iostream>
 #include <sstream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1

 const int maxn = 1e6+;
 int n, k;
 int a[maxn];
 int Q[maxn], P[maxn];
 int mn[maxn], mx[maxn];

 void getMin() {
     int l = , r = ;
     int i;

     for (i=; i<k-; ++i) {
         while (l<=r && Q[r]>=a[i])
             --r;
         Q[++r] = a[i];
         P[r] = i;
     }

     for (; i<n; ++i) {
         while (l<=r && Q[r]>=a[i])
             --r;
         Q[++r] = a[i];
         P[r] = i;
         while (P[l] < i-k+)
             ++l;
         mn[i-k+] = Q[l];
     }
 }

 void getMax() {
     int l = , r = ;
     int i;

     for (i=; i<k-; ++i) {
         while (l<=r && Q[r]<=a[i])
             --r;
         Q[++r] = a[i];
         P[r] = i;
     }

     for (; i<n; ++i) {
         while (l<=r && Q[r]<=a[i])
             --r;
         Q[++r] = a[i];
         P[r] = i;
         while (P[l] < i-k+)
             ++l;
         mx[i-k+] = Q[l];
     }
 }

 void solve() {
     getMin();
     getMax();
     rep(i, , n-k+) {
         if (i == n-k)
             printf("%d\n", mn[i]);
         else
             printf("%d ", mn[i]);
     }
     rep(i, , n-k+) {
         if (i == n-k)
             printf("%d\n", mx[i]);
         else
             printf("%d ", mx[i]);
     }
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d %d", &n, &k);
     rep(i, , n)
         scanf("%d", &a[i]);
     solve();

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }