POJ 1733 and query the Set offset Vector

Source: Internet
Author: User

The offset vector is also used.

A numerical string consisting of 0, 1 ~~, Now, you have some questions about whether the number of numbers from I to j is an odd or even number. He will tell you the answer, but the answer may be self-contradictory. Now, it is no conflict to have the first few answers.


If r [I] is set, it indicates the parity of the Number 1 from the first place to the second place. r [I] = 0 indicates that there are even numbers of 1, r [I] = 1 indicates that there is an odd number of 1.
If the I-th to j-TH is an even number of 1, r [I-1] = 1, r [j] = 1 or r [I-1] = 0, r [j] = 0 So r [I-1] ^ r [j] = 0
If it is an odd number of 1, r [I-1] = 1, r [j] = 0 or r [I-1] = 0, r [j] = 1 so r [I-1] ^ r [j] = 1


Then we can use and query the set, and use an array d [I] to represent the difference or value between r [I] and its ancestor.

If the endpoint of the two intervals has appeared before, you can determine whether the difference or value is equal to the previous one.

If it does not appear, merge it directly to update the difference or value.


[Cpp]
# Include <iostream>
# Include <vector>
# Include <map>
# Include <set>
# Include <queue>
# Include <stack>
# Include <algorithm>
# Include <cstdio>
# Include <cstdlib>
# Include <string>
# Include <cstring>
# Include <cmath>
# Define maxn22222
# Define MAXM 55555
# Define INF 100000000
Using namespace std;
Int n, m;
Int fa [MAXN];
Int l [MAXN], r [MAXN], c [MAXN];
Int x [MAXN], d [MAXN];
Int find (int x)
{
If (fa [x] = x) return x;
Int t = find (fa [x]);
D [x] ^ = d [fa [x];
Fa [x] = t;
Return t;
}
Bool join (int x, int y, int v)
{
Int fx = find (x );
Int fy = find (y );
If (fx = fy) return (d [x] ^ d [y]) = v );
Else
{
Fa [fx] = fy;
D [fx] = d [x] ^ d [y] ^ v;
Return 1;
}
}
Int bin (int low, int high, int v)
{
While (low <= high)
{
Int mid = (low + high)> 1;
If (x [mid] = v) return mid;
Else if (x [mid]> v) high = mid-1;
Else low = mid + 1;
}
Return-1;
}
Int main ()
{
Char s [15];
Scanf ("% d", & n, & m );
Int cnt = 0;
For (int I = 1; I <= m; I ++)
{
Scanf ("% d % s", & l [I], & r [I], s );
X [cnt ++] = l [I]-1;
X [cnt ++] = r [I];
If (s [0] = 'E') c [I] = 0;
Else c [I] = 1;
}
Sort (x, x + cnt );
Cnt = unique (x, x + cnt)-x;
For (int I = 1; I <MAXN; I ++) fa [I] = I, d [I] = 0;
Int fg = 0;
For (int I = 1; I <= m; I ++)
{
Int L = bin (0, cnt-1, l [I]-1) + 1;
Int R = bin (0, cnt-1, r [I]) + 1;
If (! Join (L, R, c [I])
{
Fg = 1;
Printf ("% d \ n", I-1 );
Break;
}
}
If (! Fg) printf ("% d \ n", m );
Return 0;
}

# Include <iostream>
# Include <vector>
# Include <map>
# Include <set>
# Include <queue>
# Include <stack>
# Include <algorithm>
# Include <cstdio>
# Include <cstdlib>
# Include <string>
# Include <cstring>
# Include <cmath>
# Define maxn22222
# Define MAXM 55555
# Define INF 100000000
Using namespace std;
Int n, m;
Int fa [MAXN];
Int l [MAXN], r [MAXN], c [MAXN];
Int x [MAXN], d [MAXN];
Int find (int x)
{
If (fa [x] = x) return x;
Int t = find (fa [x]);
D [x] ^ = d [fa [x];
Fa [x] = t;
Return t;
}
Bool join (int x, int y, int v)
{
Int fx = find (x );
Int fy = find (y );
If (fx = fy) return (d [x] ^ d [y]) = v );
Else
{
Fa [fx] = fy;
D [fx] = d [x] ^ d [y] ^ v;
Return 1;
}
}
Int bin (int low, int high, int v)
{
While (low <= high)
{
Int mid = (low + high)> 1;
If (x [mid] = v) return mid;
Else if (x [mid]> v) high = mid-1;
Else low = mid + 1;
}
Return-1;
}
Int main ()
{
Char s [15];
Scanf ("% d", & n, & m );
Int cnt = 0;
For (int I = 1; I <= m; I ++)
{
Scanf ("% d % s", & l [I], & r [I], s );
X [cnt ++] = l [I]-1;
X [cnt ++] = r [I];
If (s [0] = 'E') c [I] = 0;
Else c [I] = 1;
}
Sort (x, x + cnt );
Cnt = unique (x, x + cnt)-x;
For (int I = 1; I <MAXN; I ++) fa [I] = I, d [I] = 0;
Int fg = 0;
For (int I = 1; I <= m; I ++)
{
Int L = bin (0, cnt-1, l [I]-1) + 1;
Int R = bin (0, cnt-1, r [I]) + 1;
If (! Join (L, R, c [I])
{
Fg = 1;
Printf ("% d \ n", I-1 );
Break;
}
}
If (! Fg) printf ("% d \ n", m );
Return 0;
}


 

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