Meaning of the questions: Give a sequence of 01, is now free to come up with an interval, and then say the interval contains an odd number or even number 1, because there may lie, so how many you did not lie before the judge, that is, to find the first a lie position -1 sequence length \ (n-<= 1E9 \) , number of intervals \ (m <= 10000. \ )
Analysis: sideband power and extension field are able to solve personally think domain extension disjoint-set better understanding.
No time to analyze, and leave a hole, it should not come back filled.
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
#include<map>
#include<set>
#define ll long long
using namespace std;
const int N=20005;
int b[N],fa[N],d[N];
struct ppx{int x,y,z;}a[N];
inline int get(int x){
if(x==fa[x])return x;
int root=get(fa[x]);
d[x]^=d[fa[x]];
return fa[x]=root;
}
int main(){
int n,m,tot=0;scanf("%d%d",&n,&m);
for(int i=1;i<=m;++i){
char s[5];
scanf("%d%d%s",&a[i].x,&a[i].y,s);
if(s[0]=='o')a[i].z=1;
else a[i].z=0;
b[++tot]=a[i].x;b[++tot]=a[i].y;
}
sort(b+1,b+tot+1);
int sum=unique(b+1,b+tot+1)-b-1;
for(int i=1;i<=m;++i){
a[i].x=lower_bound(b+1,b+sum+1,a[i].x-1)-b;
a[i].y=lower_bound(b+1,b+sum+1,a[i].y)-b;
}
for(int i=1;i<=sum;++i)fa[i]=i;
for(int i=1;i<=m;++i){
int p=get(a[i].x),q=get(a[i].y);
if(p==q){
if(d[a[i].x]^d[a[i].y]!=a[i].z){
printf("%d\n",i-1);
return 0;
}
}
else{
fa[p]=q;d[p]=d[a[i].x]^d[a[i].y]^a[i].z;
}
}
printf("%d\n",m);
return 0;
}
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
#include<map>
#include<set>
#define ll long long
using namespace std;
const int N=40005;
int b[N],fa[N];
struct ppx{int x,y,z;}a[N];
inline int get(int x){
if(x==fa[x])return x;
return fa[x]=get(fa[x]);
}
int main(){
int n,m,tot=0;scanf("%d%d",&n,&m);
for(int i=1;i<=m;++i){
char s[5];
scanf("%d%d%s",&a[i].x,&a[i].y,s);
if(s[0]=='o')a[i].z=1;
else a[i].z=0;
b[++tot]=a[i].x;b[++tot]=a[i].y;
}
sort(b+1,b+tot+1);
int sum=unique(b+1,b+tot+1)-b-1;
for(int i=1;i<=m;++i){
a[i].x=lower_bound(b+1,b+sum+1,a[i].x-1)-b;
a[i].y=lower_bound(b+1,b+sum+1,a[i].y)-b;
}
for(int i=1;i<=2*sum;++i)fa[i]=i;
for(int i=1;i<=m;++i){
int x1=a[i].x,x2=a[i].x+sum;
int y1=a[i].y,y2=a[i].y+sum;
if(!a[i].z){
if(get(x1)==get(y2)){
printf("%d\n",i-1);
return 0;
}
fa[get(x1)]=get(y1);
fa[get(x2)]=get(y2);
}
else{
if(get(x1)==get(y1)){
printf("%d\n",i-1);
return 0;
}
fa[get(x1)]=get(y2);
fa[get(x2)]=get(y1);
}
}
printf("%d\n",m);
return 0;
}