http://poj.org/problem?id=2823// 原题链接
题目大意，就是输出每个相邻 (i,i+k+1)区间中的最大值
/// 单调队列练习
1 #include <algorithm> 2 #include <stack> 3 #include <istream> 4 #include <stdio.h> 5 #include <map> 6 #include <math.h> 7 #include <vector> 8 #include <iostream> 9 #include <queue> 10 #include <string.h> 11 #include <set> 12 #include <cstdio> 13 #define FR(i,n) for(int i=0;i<n;i++) 14 #define MAX 2005 15 #define mkp pair <int,int> 16 using namespace std; 17 #pragma comment(linker, "/STACK:10240000000,10240000000") 18 const int maxn = 1e6+5; 19 typedef long long ll; 20 const int inf = 0x3fffff; 21 void read(int &x) { 22 char ch; bool flag = 0; 23 for (ch = getchar(); !isdigit(ch) && ((flag |= (ch == '-')) || 1); ch = getchar()); 24 for (x = 0; isdigit(ch); x = (x << 1) + (x << 3) + ch - 48, ch = getchar()); 25 x *= 1 - 2 * flag; 26 } 27 int val[maxn]; 28 int Min[maxn],Max[maxn]; 29 int id[maxn],path[maxn]; 30 int main() { 31 int n,m; 32 while(~scanf("%d%d",&n,&m)){ 33 vector <int> r1; 34 vector <int> r2; 35 for(int i=0;i<n;i++)read(val[i]); 36 int tail = 1, ed = 0; 37 int head = 1, sd = 0; 38 for(int i=0;i<m-1;i++){ 39 while(val[i]<=Min[ed]&&tail<=ed){ 40 --ed; 41 } 42 43 while(val[i]>=Max[sd]&&head<=sd){ 44 --sd; 45 } 46 path[++sd]=i; 47 Max[sd]=val[i]; 48 49 id[++ed]=i; 50 Min[ed]=val[i]; 51 52 } 53 // r2.push_back(Max[head]); 54 // r1.push_back(Min[tail]); 55 for(int i=m-1;i<n;i++){ 56 //for(int j=tail;j<=ed;j++)printf("%d ",Min[j]); 57 // puts(""); 58 while(val[i]<=Min[ed]&&tail<=ed){ 59 ed--; 60 } 61 62 63 while(val[i]>=Max[sd]&&head<=sd){ 64 sd--; 65 } 66 67 path[++sd]=i; 68 Max[sd]=val[i]; 69 while(i-path[head]+1>m)head++; 70 r2.push_back(Max[head]); 71 72 id[++ed]=i; 73 Min[ed]=val[i]; 74 while(i-id[tail]+1>m) 75 { 76 tail++; 77 } 78 r1.push_back(Min[tail]); 79 } 80 int siz = r1.size(); 81 for(int i=0;i<siz;i++){ 82 printf("%d%c",r1[i],(i==(siz-1)?' ':' ')); 83 } 84 for(int i=0;i<siz;i++){ 85 printf("%d%c",r2[i],(i==(siz-1)?' ':' ')); 86 } 87 } 88 return 0; 89 }