What led to the end of the Cold War? How did US containment policies contribute to the Soviet Union’s demise?

The Cold War ended with the reunification of Germany following the fall of the Berlin Wall, which signified the collapse of communism in Germany in 1990. Other major phenomena include glasnost, or "openness," which signifies a policy of increasing openness on the part of the USSR to Western ideas. Next, the policy of perestroika (first proposed by Leanid Brezhnev) involved restructuring the economic system which, under the USSR, was centrally controlled. This allowed for incentives for Soviet citizens to participate in open markets.
Mikhail Gorbachev (who came to power in 1985) was a linchpin in the breakup of the USSR. Compared to his predecessors, Gorbachev was a very progressive president. He did not retaliate when Poland held elections and a noncommunist government was elected. Communism had previously been overthrown in Yugoslavia, Hungary, and Romania following the destruction of the Berlin Wall.
In brief, the Cold War ended with the collapse of the Soviet Union; however, this really represented the collapse of several communist dictatorships and independence movements on the part of the USSR's component territories. The independence declarations of the Ukraine, Belarus, and Russia were the proverbial straws that broke the camel's back—the camel being the Soviet bloc.
It is commonly assumed that America won the Cold War; however, America assumed a lot of debt. Many Republicans take credit for eroding the Soviet economy by means of military spending. Containment (an idea popularized by Russian specialist in the American Foreign Service, George Kennan) played a role both practically and in the spirit of the American people. Containment, simply put, was the principle of stopping communism from expanding. In a way, the animosity between China and the USSR acted on its own to enforce the policy of containment.
Nevertheless, a host of cultural forces contributed to the collapse of the Soviet Union that ended the Cold War. For example, Soviet novelist Aleksandr Solzhenitsyn drew public attention to the atrocities committed in the forced labor camps known as gulags. Czechoslovakia broke up into Slovakia and the Czech Republic after rampant student protests. Albanians, Slovenes, and Croats revolted against Serbian rule, and Lithuania declared independence. Seeing the writing on the wall, Gorbachev resigned in 1991.