Union Range

unionRange.cpp

int C[MAXN], next[MAXN];
inline int findSet(int i) {
    return (C[i] == i) ? i : (C[i] = findSet(C[i]));
}
inline int findNext(int i) {
    return (next[i] == i) ? i : (next[i] = findNext(next[i]));
}
inline void unionSet(int i, int j) {
    C[findSet(i)] = findSet(j);
}
inline void unionRange(int i, int j) {
    if(j<i)
        return;
    int g = findNext(i), last = findNext(j);
    next[i] = last;
    while(g<j) {
        next[g] = last;
        unionSet(g, g+1);
        g = findNext(g+1);
    }
}