UVa 101 - The Blocks Problem

#include <cstdio>
#include <cstring>
#include <string>
#include <iostream>
#include <vector>

using namespace std;

const int maxn = 30;
int n;
vector<int>pile[maxn];

void find_block(int a, int& p, int& h) {
for (p = 0; p < n; p++) {
for (h = 0; h < pile[p].size(); h++)
if (pile[p][h] == a) return;
}
}

void clear_above(int p, int h) {
for (int i = h + 1; i < pile[p].size(); i++) {
int b = pile[p][i];
pile[b].push_back(b);
}
pile[p].resize(h + 1);
}

void pile_onto(int p, int h, int p2) {
for (int i = h; i < pile[p].size(); i++)
pile[p2].push_back(pile[p][i]);
pile[p].resize(h);
}

void print() {
for (int i = 0; i < n; i++) {
printf("%d:", i);
for (int j = 0; j < pile[i].size(); j++)
printf(" %d", pile[i][j]);
printf("\n");
}
}

int main(void) {
int a, b;
cin >> n;
string s1, s2;
for (int i = 0; i < n; i++)
pile[i].push_back(i);
while (cin >> s1 >> a >> s2 >> b) {
int pa, pb, ha, hb;
find_block(a, pa, ha);
find_block(b, pb, hb);
if (pa == pb) continue;
if (s2 == "onto") clear_above(pb, hb);
if (s1 == "move") clear_above(pa, ha);
pile_onto(pa, ha, pb);
}
print();
return 0;
}