137 lines
4.2 KiB
TypeScript
137 lines
4.2 KiB
TypeScript
module es {
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/**
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* 这个类可以从两方面来考虑。你可以把它看成一个位向量或者一组非负整数。这个名字有点误导人。
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*
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* 它是由一个位向量实现的，但同样可以把它看成是一个非负整数的集合;集合中的每个整数由对应索引处的集合位表示。该结构的大小由集合中的最大整数决定。
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*/
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export class BitSet {
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private static LONG_MASK: number = 0x3f;
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private _bits: number[];
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constructor(nbits: number = 64) {
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let length = nbits >> 6 >>> 0;
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if ((nbits & BitSet.LONG_MASK) != 0)
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length++;
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this._bits = new Array(length);
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this._bits.fill(0);
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}
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public and(bs: BitSet) {
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let max = Math.min(this._bits.length, bs._bits.length);
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let i;
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for (let i = 0; i < max; ++i)
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this._bits[i] &= bs._bits[i];
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while (i < this._bits.length)
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this._bits[i++] = 0;
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}
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public andNot(bs: BitSet) {
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let i = Math.min(this._bits.length, bs._bits.length);
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while (--i >= 0)
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this._bits[i] &= ~bs._bits[i];
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}
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public cardinality(): number {
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let card = 0 >>> 0;
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for (let i = this._bits.length - 1; i >= 0; i--) {
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let a = this._bits[i];
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if (a == 0)
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continue;
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if (a == -1) {
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card += 64;
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continue;
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}
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a = ((a >> 1) & 0x5555555555555555) + (a & 0x5555555555555555);
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a = ((a >> 2) & 0x3333333333333333) + (a & 0x3333333333333333);
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let b = ((a >> 32) + a) >>> 0;
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b = ((b >> 4) & 0x0f0f0f0f) + (b & 0x0f0f0f0f);
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b = ((b >> 8) & 0x00ff00ff) + (b & 0x00ff00ff);
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card += ((b >> 16) & 0x0000ffff) + (b & 0x0000ffff);
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}
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return card;
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}
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public clear(pos?: number) {
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if (pos != undefined) {
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let offset = pos >> 6;
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this.ensure(offset);
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this._bits[offset] &= ~(1 << pos);
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} else {
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for (let i = 0; i < this._bits.length; i++)
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this._bits[i] = 0;
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}
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}
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public get(pos: number): boolean {
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let offset = pos >> 6;
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if (offset >= this._bits.length)
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return false;
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return (this._bits[offset] & (1 << pos)) != 0;
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}
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public intersects(set: BitSet) {
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let i = Math.min(this._bits.length, set._bits.length);
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while (--i >= 0) {
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if ((this._bits[i] & set._bits[i]) != 0)
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return true;
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}
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return false;
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}
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public isEmpty(): boolean {
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for (let i = this._bits.length - 1; i >= 0; i--) {
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if (this._bits[i])
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return false;
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}
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return true;
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}
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public nextSetBit(from: number) {
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let offset = from >> 6;
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let mask = 1 << from;
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while (offset < this._bits.length) {
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let h = this._bits[offset];
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do {
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if ((h & mask) != 0)
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return from;
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mask <<= 1;
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from++;
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} while (mask != 0);
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mask = 1;
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offset++;
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}
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return -1;
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}
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public set(pos: number, value: boolean = true) {
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if (value) {
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let offset = pos >> 6;
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this.ensure(offset);
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this._bits[offset] |= 1 << pos;
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} else {
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this.clear(pos);
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}
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}
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private ensure(lastElt: number) {
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if (lastElt >= this._bits.length) {
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let startIndex = this._bits.length;
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this._bits.length = lastElt + 1;
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this._bits.fill(0, startIndex, lastElt + 1);
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}
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}
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}
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}
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