习题8-6　起重机（Crane, ACM/ICPC CERC 2013, UVa1611）

#include <set>
#include <map>
#include <ctime>
#include <cmath>
#include <stack>
#include <queue>
#include <deque>
#include <cstdio>
#include <string>
#include <vector>
#include <cctype>
#include <sstream>
#include <utility>
#include <cstring>
#include <cstdlib>
#include <functional>
#include <iostream>
#include <algorithm>
#define SF(a) scanf("%d", &a)
#define PF(a) printf("%d\n", a)
#define SFF(a, b) scanf("%d%d", &a, &b)
#define SFFF(a, b, c) scanf("%d%d%d", &a, &b, &c)
#define SFFFF(a, b, c, d) scanf("%d%d%d%d", &a, &b, &c, &d)
#define CLEAR(a, b) memset(a, b, sizeof(a))
#define IN() freopen("in.txt", "r", stdin)
#define OUT() freopen("out.txt", "w", stdout)
#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define ALL(a) (a).begin(), (a).end()
#define SZ(a) (int)(a).size()
#define PB push_back
#define LL long long
#define mod 10007
#define inf 107
#define eps 1e-12
using namespace std;
int buf[20];
int read() {
int x = 0; char ch = getchar(); bool f = 0;
while (ch < '0' || ch > '9') { if (ch == '-') f = 1; ch = getchar(); }
while (ch >= '0' && ch <= '9') x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
return f ? -x : x;
}
void write(int x) {
if (!x) { putchar(48); return; }
int l = 0; if (x < 0) putchar('-'), x = -x;
while (x) buf[++l] = x % 10, x = x / 10;
while (l) putchar(buf[l--] + 48);
}
//-------------------------chc------------------------------//
const int maxn = 10005;
int a[maxn];
int n;
typedef pair<int, int> pii;
int cnt;
vector<pii> v;

void debug() {
FOR(i, 1, n + 1) printf("a = %d\n", a[i]);
}

void crane(int l, int r, int m) {
cnt++;
v.push_back(pii(l, r));
int num = (r - l + 1) / 2;
FOR(i, 0, num)
swap(a[l + i], a[m + i]);
//printf("l = %d, r = %d, m = %d\n", l, r, m);
//debug();
}

int find(int cur) {
int ret;
FOR(i, cur, n + 1)
if (a[i] == cur) {
ret = i;
break;
}
return ret;
}

void solve() {
int cur = 1;
while (cur <= n) {
int pos = find(cur);
if (pos == cur) { cur++; continue; }
int l = cur, r = pos;
if ((pos - cur + 1) & 1) l++;
crane(l, r, (l + r + 1)/2);

pos -= ((r - l + 1) / 2);
if (pos == cur) { cur++; continue; }
l = cur;
r = pos + (pos - l - 1);
crane(l, r, (l + r + 1)/2);
cur++;
}
}

int main() {
//IN(); OUT();
int t = read();
while (t--) {
v.clear();
cnt = 0;
SF(n);
FOR(i, 1, n + 1) SF(a[i]);
solve();
PF(cnt);
FOR(i, 0, SZ(v)) printf("%d %d\n", v[i].first, v[i].second);
//debug();
}
return 0;
}