UVa 12299 - RMQ with Shifts

题目链接：

线段树，点修改。

  1 #include <cstdio>

  2 #include <cctype>

  3 #define lson l, m, rt << 1

  4 #define rson m + 1, r, ( rt << 1 ) | 1

  5 

  6 const int MAXN = 100010;

  7 const int INF = 2147483645;

  8 

  9 int tree[ MAXN << 2 ];

 10 

 11 int min( int a, int b )

 12 {

 13     return a < b ? a : b;

 14 }

 15 

 16 void PushUP( int rt )

 17 {

 18     tree[rt] = min( tree[rt << 1] , tree[ rt << 1 | 1 ] );

 19     return;

 20 }

 21 

 22 void build( int l, int r, int rt )

 23 {

 24     if ( l == r )

 25     {

 26         scanf( "%d", &tree[rt] );

 27         return;

 28     }

 29     int m = ( l + r ) >> 1;

 30     build(lson);

 31     build(rson);

 32     PushUP(rt);

 33 }

 34 

 35 void update( int p, int e, int l, int r, int rt )

 36 {

 37     if ( l == r )

 38     {

 39         tree[rt] = e;

 40         return;

 41     }

 42     int m = ( l + r ) >> 1;

 43     if ( p <= m ) update( p, e, lson );

 44     else update( p, e, rson );

 45     PushUP(rt);

 46     return;

 47 }

 48 

 49 void GetNum( int p, int &e, int l, int r, int rt )

 50 {

 51     if ( l == r )

 52     {

 53         e = tree[rt];

 54         return;

 55     }

 56     int m = ( l + r ) >> 1;

 57     if ( p <= m ) GetNum( p, e, lson );

 58     else GetNum( p, e, rson );

 59     return;

 60 }

 61 

 62 int Query( int L, int R, int l, int r, int rt )

 63 {

 64     if ( L <= l && R >= r )

 65        return tree[rt];

 66 

 67     int ret = INF;

 68     int m = ( l + r ) >> 1;

 69     if ( L <= m ) ret = min( ret, Query( L, R, lson ) );

 70     if ( R > m ) ret = min( ret, Query( L, R, rson ) );

 71     return ret;

 72 }

 73 

 74 int main()

 75 {

 76     int n, Q;

 77     char order[50];

 78     int addr[50], number[50];

 79     while ( ~scanf( "%d%d", &n, &Q ) )

 80     {

 81         build( 1, n, 1 );

 82         while ( Q-- )

 83         {

 84             scanf( "%s", order );

 85             if ( order[0] == 'q' )

 86             {

 87                 int x, y;

 88                 sscanf( order, "query(%d,%d)", &x, &y );

 89 //                printf("##%d %d\n", x, y);

 90                 printf( "%d\n", Query( x, y, 1, n, 1 ) );

 91             }

 92             else

 93             {

 94                 int cnt = 0;

 95                 for ( int i = 0; order[i]; )

 96                 {

 97                     if ( isdigit( order[i] ) )

 98                     {

 99                         int sum = 0;

100                         while ( isdigit( order[i] ) )

101                             sum = sum * 10 + order[i++] - '0';

102                         addr[cnt++] = sum;

103                     }

104                     else ++i;

105                 }

106 

107                 for ( int i = 0; i < cnt; ++i )

108                 {

109                //     printf( "=%d ", addr[i] );

110                     GetNum( addr[i], number[i], 1, n, 1 );

111                //     printf( "@%d\n", number[i] );

112                 }

113                 for ( int i = 0; i < cnt; ++i )

114                 {

115                     if ( i == cnt - 1 ) update( addr[i], number[0], 1, n, 1 );

116                     else update( addr[i], number[i + 1], 1, n, 1 );

117                 }

118             }

119         }

120     }

121     return 0;

122 }