This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/problems/DSL_1_B"
#include "../../../src/template/template.hpp"
#include "../../../src/data_structure/weighted_union_find.hpp"
int main(void) {
int n, q;
cin >> n >> q;
WeightedUnionFind<int> uf(n);
while(q--) {
int t;
cin >> t;
if(t == 0) {
int x, y, z;
cin >> x >> y >> z;
uf.merge(y, x, z);
} else {
int x, y;
cin >> x >> y;
if(uf.same(x, y)) {
cout << uf.diff(y, x) << '\n';
} else {
cout << '?' << '\n';
}
}
}
}
#line 1 "verify/aizu_online_judge/dsl/weighted_union_find_trees.test.cpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/problems/DSL_1_B"
#line 2 "src/template/template.hpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<long long, long long>;
#define rep(i, a, b) for(long long i = (a); i < (b); ++i)
#define rrep(i, a, b) for(long long i = (a); i >= (b); --i)
constexpr long long inf = 4e18;
struct SetupIO {
SetupIO() {
ios::sync_with_stdio(0);
cin.tie(0);
cout << fixed << setprecision(30);
}
} setup_io;
#line 3 "src/data_structure/weighted_union_find.hpp"
template <typename T>
struct WeightedUnionFind {
WeightedUnionFind(const int N)
: n(N), data(N, -1), ws(N, T()) {}
bool merge(const int a, const int b, T w) {
assert(0 <= a and a < n);
assert(0 <= b and b < n);
w += weight(b) - weight(a);
int x = leader(a), y = leader(b);
if(x == y) return w == T();
if(-data[x] > -data[y]) swap(x, y), w = -w;
data[y] += data[x];
data[x] = y;
ws[x] = w;
return true;
}
bool same(const int a, const int b) {
assert(0 <= a and a < n);
assert(0 <= b and b < n);
return leader(a) == leader(b);
}
int leader(const int a) {
assert(0 <= a and a < n);
if(data[a] < 0) return a;
const int r = leader(data[a]);
ws[a] += ws[data[a]];
return data[a] = r;
}
int size(const int a) {
assert(0 <= a and a < n);
return -data[leader(a)];
}
T weight(const int a) {
assert(0 <= a and a < n);
leader(a);
return ws[a];
}
T diff(const int a, const int b) {
assert(0 <= a and a < n);
assert(0 <= b and b < n);
return weight(a) - weight(b);
}
private:
int n;
vector<int> data;
vector<T> ws;
};
#line 4 "verify/aizu_online_judge/dsl/weighted_union_find_trees.test.cpp"
int main(void) {
int n, q;
cin >> n >> q;
WeightedUnionFind<int> uf(n);
while(q--) {
int t;
cin >> t;
if(t == 0) {
int x, y, z;
cin >> x >> y >> z;
uf.merge(y, x, z);
} else {
int x, y;
cin >> x >> y;
if(uf.same(x, y)) {
cout << uf.diff(y, x) << '\n';
} else {
cout << '?' << '\n';
}
}
}
}