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算法竞赛入门经典(第2版) 6-4UVa439 6-5UVa1600

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比较忙比较累，只贴代码了。

题目：6-4 UVa439 - Knight Moves

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//UVa439 - Knight Moves
//Accepted 0.000s
//#define _XIENAOBAN_
#include<iostream>
#include<cstring>
#include<queue>
#define M(po) Map[po.x][po.y]
using namespace std;

struct poi {
	int x, y, weight;
	poi operator +(const poi &that) const {
		return poi{ x + that.x, y + that.y, weight};
	}
	bool operator ==(const poi &that) const {
		return (x == that.x) && (y == that.y);
	}
} op, ed;

const poi dir[8] = { { 2,1 },{ -2,1 },{ 2,-1 },{ -2,-1 },{ 1,2 },{ -1,2 },{ 1,-2 },{ -1,-2 } };
bool Map[10][10];
char xstart, ystart, xend, yend;
int xs, ys, xe, ye;

int BFS(){
	if (op == ed) return 0;
	queue<poi> Q;
	Q.push(op);
	M(op) = true;
	while (!Q.empty()) {
		for (int i(0);i < 8;++i){
			poi nxt(Q.front() + dir[i]);
			if (nxt.x > 0 && nxt.y > 0 && nxt.x < 9 && nxt.y < 9 && !M(nxt)) {
				++nxt.weight;
				if (nxt == ed) return nxt.weight;
				M(nxt) = true;
				Q.push(nxt);
			}
		}
		Q.pop();
	}
	return -1;
}


int main()
{
#ifdef _XIENAOBAN_
#define gets(T) gets_s(T, 129)
	freopen("in.txt", "r", stdin);
	//freopen("out.txt", "w", stdout);
#endif

	while (scanf("%c%c %c%c", &xstart, &ystart, &xend, &yend) == 4) {
		memset(Map, 0, sizeof(Map));
		op.x = xstart - 96, op.y = ystart - 48, op.weight = 0;
		ed.x = xend - 96, ed.y = yend - 48, ed.weight = 0;
		printf("To get from %c%c to %c%c takes %d knight moves.\n", xstart, ystart, xend, yend, BFS());
		while (getchar() != '\n');
	}
	return 0;
}

题目：6-5 UVa1600 - Patrol Robot 

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//UVa1600 - Patrol Robot
//Accepted 0.000s
//#define _XIENAOBAN_
#include<iostream>
#include<cstring>
#include<queue>
#define DONE 2333333
using namespace std;

struct step { int x, y, k, mov; };
int T, m, n, k;
int Map[24][24],Obst[24][24];

void judge(queue<step> &Q, step &now, int x, int y) {
	if (Obst[x += now.x][y += now.y] == DONE) return;
	int _k = (Obst[x][y] ? now.k + 1 : 0);
	if (_k <= k) {
		if (_k) {
			if (Map[x][y] && Map[x][y] <= _k) return;
			Map[x][y] = _k;
		}
		else Obst[x][y] = DONE;
		Q.push(step{ x, y, _k, now.mov + 1 });
	}
}

int main()
{
#ifdef _XIENAOBAN_
#define gets(T) gets_s(T, 129)
	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w", stdout);
#endif

	scanf("%d", &T);
	while (T--) {
		scanf("%d%d%d", &m, &n, &k);
		for (int i(1);i <= m;++i) for (int j(1);j <= n;++j)
			scanf("%d", &Obst[i][j]);
		memset(Map, 0, sizeof(Map));
		queue<step> Q;
		Q.push(step{ 1,1,0,0 });
		Obst[1][1] = DONE;
		while (!Q.empty()) {
			step &now(Q.front());
			if (now.x == m && now.y == n) break;
			if (now.x + 1 <= m) judge(Q, now, 1, 0);
			if (now.y + 1 <= n) judge(Q, now, 0, 1);
			if (now.x - 1 >= 1) judge(Q, now, -1, 0);
			if (now.y - 1 >= 1) judge(Q, now, 0, -1);
			Q.pop();
		}
		if (Q.empty()) printf("-1\n");
		else printf("%d\n", Q.front().mov);
	}
	return 0;
}