1 #include <iostream> 2 #include <math.h> 3 #include <cstdio> 4 #define max(a,b) ((a)>(b)?(a):(b)) 5 #define min(a,b) ((a)<(b)?(a):(b)) 6 7 using namespace std; 8 9 const int maxn=50001; 10 int h[maxn]; 11 int mx[maxn][16],mn[maxn][16]; 12 int n,q; 13 14 void rmq_init() 15 { 16 int i,j; 17 for(j=1;j<=n;j++) mx[j][0]=mn[j][0]=h[j]; 18 int m=floor(log((double)n)/log(2.0)); 19 for(i=1;i<=m;i++){ 20 for(j=n;j>0;j--){ 21 mx[j][i]=mx[j][i-1]; 22 if(j+(1<<(i-1))<=n) mx[j][i]=max(mx[j][i],mx[j+(1<<(i-1))][i-1]); 23 } 24 } 25 for(i=1;i<=m;i++){ 26 for(j=n;j>0;j--){ 27 mn[j][i]=mn[j][i-1]; 28 if(j+(1<<(i-1))<=n) mn[j][i]=min(mn[j][i],mn[j+(1<<(i-1))][i-1]); 29 } 30 } 31 } 32 33 int rmq(int l,int r) 34 { 35 int m=floor(log((double)(r-l+1))/log(2.0)); 36 int a=max(mx[l][m],mx[r-(1<<m)+1][m]); 37 int b=min(mn[l][m],mn[r-(1<<m)+1][m]); 38 return a-b; 39 } 40 41 int main() 42 { 43 freopen("input.txt","r",stdin); 44 int i,l,r; 45 int num; 46 scanf("%d",&num); 47 for(int jj=1;jj<=num;jj++){ 48 scanf("%d%d",&n,&q); 49 for(i=1;i<=n;i++) scanf("%d",&h[i]); 50 rmq_init(); 51 printf("Test case #%d:\n",jj); 52 for(i=0;i<q;i++){ 53 scanf("%d%d",&l,&r); 54 printf("%d\n",rmq(l,r)); 55 } 56 57 } 58 return 0; 59 } 60 用这个了 61 思路比较清晰 速度也不慢
1 template < class Type> 2 class rmq_st{ 3 private: 4 Type* body; 5 int** mi; 6 int size; 7 int len; 8 9 int dint(double a){ 10 int buf=a; 11 if(buf>a){ 12 --buf; 13 } 14 return buf; 15 } 16 17 int mlen(int l,int r){ 18 double buf=log((double)(r-l+1))/log((double)2); 19 return dint(buf) 20 } 21 bool (*less)(Type& t1,Type& t2); 22 23 public: 24 25 26 //构造函数 : (待求数组,大小,小于函数) 27 rmq_st(Type* con,int s,bool (*lessthan)(Type& t1,Type& t2)); 28 29 ~rmq_st();//解构 30 31 Type get_body(int p);//返回指定索引的元素 32 33 int query_index(int l,int r);//返回指定区间最小值的元素索引 34 35 Type query(int l,int r);//返回指定区间的最小元素 36 }; 37 38 template < class Type> 39 rmq_st< Type>::rmq_st(Type* con,int s,bool (*lessthan)(Type& t1,Type& t2)){ 40 less=lessthan; 41 body=con; 42 size=s; 43 len=mlen(0,s-1)+1; 44 mi=new int*[size]; 45 int i,j; 46 for(i=0;i< size;++i){ 47 mi[i]=new int[len]; 48 } 49 int bound; 50 int a,b; 51 for(i=0;i< size;++i){ 52 mi[i][0]=i; 53 } 54 for(i=1;i< len;++i){ 55 bound=n-(1<< i)+1; 56 for(j=0;j< bound;++j){ 57 a=mi[j][i-1]; 58 b=mi[j+(1<< (i-1))][i-1]; 59 mi[j][i]=less(body[a],body[b])?a:b; 60 } 61 } 62 } 63 64 template < class Type> 65 rmq_st< Type>::~rmq_st(){ 66 int i; 67 for(i=0;i< size;++i){ 68 delete[] mi[i]; 69 } 70 delete[] mi; 71 } 72 73 template < class Type> 74 Type rmq_st< Type>::get_body(int p){ 75 return body[p]; 76 } 77 78 template < class Type> 79 int rmq_st< Type>::query_index(int l,int r){ 80 int length=mlen(l,r); 81 int a=mi[l][length]; 82 int b=mi[r-(1<< length)+1][length]; 83 return less(body[a],body[b])?a:b; 84 } 85 86 template < class Type> 87 Type rmq_st< Type>::query(int l,int r){ 88 int length=mlen(l,r); 89 int a=mi[l][length]; 90 int b=mi[r-(1<< length)+1][length]; 91 return less(body[a],body[b])?body[a]:body[b]; 92 } 93 94 /*----------------Example : POJ 3264 Memory:7708K Time:3230MS-----------------*/ 95 96 int cow[50001]; 97 int n,q; 98 99 bool cmpmin(int& t1,int& t2){ 100 return t1< t2; 101 } 102 103 bool cmpmax(int& t1,int& t2){ 104 return t1>t2; 105 } 106 107 int main() 108 { 109 // freopen("1.in","r",stdin); 110 scanf("%d %d",&n,&q); 111 int i; 112 for(i=0;i< n;++i){ 113 scanf("%d",&cow[i]); 114 } 115 rmq_st< int> minst(cow,n,cmpmin); 116 rmq_st< int> maxst(cow,n,cmpmax); 117 int a,b; 118 for(i=0;i< q;++i){ 119 scanf("%d %d",&a,&b); 120 --a; 121 --b; 122 printf("%d\n",maxst.query(a,b)-minst.query(a,b)); 123 } 124 return 0; 125 }
342ms.................